Showing 1–50 of 538 results for author: Collins, K

Advancing Open and Reproducible Relational Learning: RelArena-$α$, TabPFN-Rel and RPI

Authors: Adrian Hayler, Klemens Flöge, Alan Arazi, Rishabh Ranjan, Jure Leskovec, Felix Birkel, Brendan Roof, Anurag Garg, Kristina Collins, Lydia Sidhoum, Jonas Kübler, Siyuan Guo, Oscar Key, Jan Hendrik Metzen, Rylee Grace, David Salinas, Arthur Cahu, Simon Bing, Benjamin Jäger, Tuana Çelik, Mihir Manium, Vitor Monteiro, Jake Robertson, Jerry Chen, Eliott Kalfon , et al. (22 additional authors not shown)

Abstract: This first release of Prior Labs in relational learning shows our continued commitment to open science. We open-source three pieces of software that we expect to accelerate research in the field towards meaningful real-world impact. We aim to steer further development based on feedback from, and in collaboration with, the community. Given the early stage of development, our $α$-release targets res… ▽ More This first release of Prior Labs in relational learning shows our continued commitment to open science. We open-source three pieces of software that we expect to accelerate research in the field towards meaningful real-world impact. We aim to steer further development based on feedback from, and in collaboration with, the community. Given the early stage of development, our $α$-release targets researchers and early-adopting practitioners. Over the past years, a variety of datasets and tasks for relational learning have emerged, but the community has not converged on a reliable, reproducible way to compare different methods on these tasks. Our $α$-release, RelArena-$α$, provides a unified framework for running and comparing baselines on RelBench v1 by standardizing data loading, evaluation protocols, tuning regimes, and support for systems with custom tuning, inspired by established tabular benchmarks such as TabArena. We plan to work with the research community to further develop RelArena-$α$ into a catalyst for progress in the relational learning community. We release the initial version of TabPFN-Rel, a purpose-built relational harness for TabPFN-3. Currently ranked first among models on RelArena-$α$, TabPFN-Rel makes key improvements upon RDBLearn. Beyond its ranking, TabPFN-Rel serves as a strong baseline, adding to the growing evidence that flattening a relational database into a single table remains competitive with specialized relational architectures on real-world tasks. To facilitate adoption of relational learning methods in research and industry, we release an initial $α$-version of our Relational Predictive Interface, RPI, an open-source, model-agnostic interface that enables early adopters to easily define problems on new databases and apply any model implemented in RelArena-$α$, including TabPFN-Rel, to these problems. △ Less

Submitted 17 August, 2026; originally announced August 2026.

A Pair of Warm Saturn-mass Planets near the 2:1 Mean Motion Resonance around TOI-3850

Authors: Sean Collins, Michelle Kunimoto, Nicolas B. Cowan, Keivan G. Stassun, Jack J. Lissauer, Ze'ev Vladimir, Teo Močnik, Ernesto Elenter, David W. Latham, Karen A. Collins, Jacob Bean, Stephanie Striegel, Khalid Barkaoui, Ritvik Basant, Tanya Das, Raquel Forés-Toribio, Akihiko Fukui, Jose A. Muñoz, Felipe Murgas, Enric Palle, Ivan A. Strakhov, Richard P. Schwarz, Avi Shporer, Gregor Srdoc, Chris Stockdale , et al. (2 additional authors not shown)

Abstract: Warm Jupiters, with orbital periods of $10$--$200~\rm{days}$ and radii exceeding $8~R_{\oplus}$, are a relatively understudied class of exoplanets occupying the parameter space between hot Jupiters and more widely separated, colder Jupiter analogs. In this work, we report the detection of a multi-planet warm Jupiter system around TOI-3850 (TIC-143008050), a moderately active, near-solar metallicit… ▽ More Warm Jupiters, with orbital periods of $10$--$200~\rm{days}$ and radii exceeding $8~R_{\oplus}$, are a relatively understudied class of exoplanets occupying the parameter space between hot Jupiters and more widely separated, colder Jupiter analogs. In this work, we report the detection of a multi-planet warm Jupiter system around TOI-3850 (TIC-143008050), a moderately active, near-solar metallicity G0 dwarf star observed by TESS in Sectors 15, 21, 41, 48 and 75. Initially, a single candidate planet was discovered by TESS, displaying transit timing variations (TTVs) with an amplitude of $\sim 1~\rm hr$ and a super-period of $513~\rm days$. Through a combination of transit photometry, radial velocity observations with MAROON-X, and TTV modeling, we identify two planets: TOI-3850 b $(P_b=14.484\pm0.002~\mathrm{days},~ M_b =112\pm20~M_{\oplus},~e_b = 0.018\pm0.008, R_b = 12.07\pm0.09~R_{\oplus}, ~T_{\rm{eq}}=841\pm10~\rm{K})$, a transiting warm Jupiter, and TOI-3850 c $(P_c=29.85\pm0.01~\mathrm{days},~ M_c =90\pm15~M_{\oplus},~e_c < 0.015, ~T_{\rm{eq}}=661\pm7~\rm{K})$, a non-transiting, Saturn-mass companion. The two planets lie wide of the 2:1 mean motion resonance $(P_c/P_b \approx 2.06)$, consistent with a formation history involving disk-driven migration. $N$-body integrations indicate that TOI-3850 c may begin to transit on decadal timescales, while TOI-3850 b remains a promising target for follow-up atmospheric characterization. △ Less

Submitted 11 August, 2026; originally announced August 2026.

Comments: 25 pages, 13 figures, 7 tables, submitted AAS journals. Comments welcome

The TASSIE Program. II: Three Close-In Companions Orbiting Sun-Like Stars

Authors: T. Plunkett, E. Thygesen, A. A. Cole, J. Schulte, J. E. Rodriguez, B. Emptage, J. P. Beaulieu, G. Bakos, J. Hartman, C. Ziegler, K. A. Collins, Z. Csubry, K. Penev, A. Jordán, R. Brahm, L. Mancini, T. Henning, D. J. Radford, P. Evans

Abstract: We present three southern transiting giant planet candidates alerted by the Transiting Exoplanet Survey Satellite (TESS) mission and investigated at the University of Tasmania Greenhill Observatory (UTGO). The candidate planets are orbiting thin disk G-dwarf main-sequence stars with roughly solar metallicity, possessing orbital periods between 2.9 - 3.3 days and radii of 1.1 - 1.3 $R_{J}$. We perf… ▽ More We present three southern transiting giant planet candidates alerted by the Transiting Exoplanet Survey Satellite (TESS) mission and investigated at the University of Tasmania Greenhill Observatory (UTGO). The candidate planets are orbiting thin disk G-dwarf main-sequence stars with roughly solar metallicity, possessing orbital periods between 2.9 - 3.3 days and radii of 1.1 - 1.3 $R_{J}$. We performed ground-based follow-up photometry primarily with the UTGO Harlingten 50 cm, then gathered reconnaissance spectra, high angular resolution imaging and high-precision radial velocities to rule out false positive scenarios. We confirmed that two of these systems host true exoplanets and constrained their masses. TOI-3053b is a typical hot Jupiter, with $M_{3053b} = 0.85 \pm 0.12$ M$_{J}$ and a bulk density of $ρ_{3053b} = 0.64 \pm 0.10$ g cm$^{-3}$. TOI-3278b / HATS-78b is a hot Saturn-mass planet ($M_{3278b} = 0.30 \pm 0.07$ $M_{J}$) with a highly inflated atmosphere and a low density of $ρ_{3278b} = 0.21 \pm 0.05$ g cm$^{-3}$. The other candidate (TOI-3272.01) remains unconfirmed, but appears consistent with being a hot Jupiter. TOI-3272.01 is notable as a candidate planet orbiting a potentially young to intermediate age star, with a rotational analysis indicating an age estimate of $T_{3272} = 1.1 \pm 0.2$ Gyr. These systems add to a growing sample of hot giant planets from TESS that may provide constraints on the migration pathways and radius inflation of the broader close-in exoplanet population. △ Less

Submitted 5 August, 2026; originally announced August 2026.

Comments: Accepted for publication in PASA. 25 pages (14 page main text + 11 page appendix/references), 18 figures, 9 tables

AI-Based Sound Effect Generation: A Narrative Review of Generative Models Across Input Modalities

Authors: Sandy Abdo, Bill Kapralos, Priyamvada Tripathi, KC Collins, Adam Dubrowski

Abstract: Sound effects play a crucial role in conveying actions, events, and environmental cues across digital applications, often requiring a high degree of variation and contextual adaptability. Artificial intelligence (AI)-driven audio generative models are rapidly growing in popularity and have the potential to transform the way sound is synthesized and used across various applications. In response to… ▽ More Sound effects play a crucial role in conveying actions, events, and environmental cues across digital applications, often requiring a high degree of variation and contextual adaptability. Artificial intelligence (AI)-driven audio generative models are rapidly growing in popularity and have the potential to transform the way sound is synthesized and used across various applications. In response to this growing momentum, this chapter reviews and analyzes recent AI-based generative models for sound effect synthesis, with a focus on how different input modalities (text, visual, audio, and multimodal) affect the quality, controllability, and contextual relevance of the generated audio. It examines 30 peer-reviewed articles sourced from Google Scholar, IEEE Xplore, and the ACM Digital Library, exploring the evolution of AI generative models over the past five years. The results show that multiple models achieved state-of-the-art performance, producing high-fidelity, semantically aligned, and increasingly temporally coherent sound effects across tasks. However, despite these advances, the review identifies persistent challenges, including limitations in temporal synchronization for complex multi-event scenarios, gaps between objective metrics and human perception, and trade-offs between controllability and generative diversity. Overall, the chapter highlights that AI-driven sound effect generation is progressing toward more adaptive, scalable, and context-aware systems, offering significant implications for future sound design workflows and interactive media applications. △ Less

Submitted 4 August, 2026; originally announced August 2026.

Comments: 29 pages, 5 figures, to appear in G. A. Tsihrintzis, M. Virvou, N. Bourbakis, and L. C. Jain (Eds.), Advances in Global Applied Artificial Intelligence: Springer, Learning and Analytics in Intelligent Systems Book Series

CAFE follow-up of TESS hot Jupiter candidates left behind: I. Five newly confirmed planets and a false positive

Authors: J. Lillo-Box, C. Cifuentes, O. Balsalobre-Ruza, B. Montesinos, D. Latham, K. A. Collins, D. Ciardi, G. Hébrard, S. W. Yee, E. W. Guenther, H. Bouy, J. N. Winn, S. B. Howell, C. Ziegler, M. E. Everett, B. Safonov, F. Murgas, N. Narita, L. D. Nielsen, A. Abreu, J. Aceituno, J. F. Agüí Fernández, M. Azzaro, D. Barrado, P. Benni , et al. (34 additional authors not shown)

Abstract: Hot Jupiters are key targets for understanding planet formation, migration, and atmospheres. Yet, most ground-based follow-up resources for the TESS mission are focused on confirming low-mass planet candidates, leaving many giant planets without mass determinations or definitive confirmation. We use the \cafe{} spectrograph at Calar Alto Observatory to monitor the radial velocity of stars hosting… ▽ More Hot Jupiters are key targets for understanding planet formation, migration, and atmospheres. Yet, most ground-based follow-up resources for the TESS mission are focused on confirming low-mass planet candidates, leaving many giant planets without mass determinations or definitive confirmation. We use the \cafe{} spectrograph at Calar Alto Observatory to monitor the radial velocity of stars hosting hot-Jupiter candidates that have received little follow-up, aiming to confirm their planetary nature. We present results for seven candidates. We monitored the radial velocity of TOI-603, TOI-1137, TOI-1837, TOI-2114, TOI-4492, TOI-5806, and TOI-5811, jointly modeling the CAFE radial velocities and TESS photometry to determine the nature and properties of the transiting objects. We confirm five new planets: TOI-603 b ($33.0^{+6.5}_{-6.2}$ M$_{\oplus}$, $16.2$ d), TOI-2114 b ($1.01^{+0.14}_{-0.12}$ M$_{\rm Jup}$, $6.2$ d), TOI-4492 b ($5.92^{+0.67}_{-0.64}$ M$_{\rm Jup}$, $4.4$ d), TOI-5806 b ($2.77^{+0.34}_{-0.32}$ M$_{\rm Jup}$, $3.2$ d), and TOI-5811 B b ($0.81^{+0.11}_{-0.10}$ M$_{\rm Jup}$, $6.3$ d). TOI-603 b lies in the "Neptune savanna", whereas the other four are hot Jupiters orbiting slightly evolved stars. We find TOI-5811.01 to be a planet transiting the nearby bound companion TOI-5811 B (hence TOI-5811 B b), and identify a stellar companion to TOI-5806 at a projected separation of 248 au, making both S-type planetary systems. TOI-1837.01 is an eclipsing binary, while TOI-1137.01 remains inconclusive. The five confirmed planets orbit bright stars (${\rm G}=8.6-10.2$~mag), and four are excellent targets for atmospheric studies, with transmission spectroscopy metrics above 90. These results highlight the importance of intensive follow-up observations to establish the nature of transiting planet candidates. △ Less

Submitted 22 July, 2026; originally announced July 2026.

Comments: Accepted for publication in A&A. 23 pages (12 of main text), 11 figures, 7 tables

Stellar Multiplicity of M Dwarfs with Short-period Giant Planets, and the Characterization of TOI-5628Ab

Authors: Tianjun Gan, Alexandrine L'Heureux, Charles Cadieux, Shude Mao, Enric Pallé, Sharon X. Wang, Keivan G. Stassun, Steve B. Howell, Benjamin V. Rackham, Steffani M. Grondin, Khalid Barkaoui, Luc Arnold, Étienne Artigau, Artem Burdanov, Adam J. Burgasser, Douglas A. Caldwell, David R. Ciardi, Karen A. Collins, Neil J. Cook, René Doyon, Georgina Dransfield, Akihiko Fukui, Michaël Gillon, Emmanuel Jehin, Felipe Murgas , et al. (11 additional authors not shown)

Abstract: Binary stars are ubiquitous, yet it remains unclear how wide-orbit stellar companions influence the formation of hot Jupiters, particularly around M dwarfs. Here, we first report the discovery of TOI-5628Ab, a giant planet transiting a mid-type M dwarf ($M_\ast=0.36\pm0.02\ M_\odot$) every 4.34 days, accompanied by an associated white dwarf TOI-5628B ($M_{\rm WD}=0.59\pm0.16\ M_\odot$) at a projec… ▽ More Binary stars are ubiquitous, yet it remains unclear how wide-orbit stellar companions influence the formation of hot Jupiters, particularly around M dwarfs. Here, we first report the discovery of TOI-5628Ab, a giant planet transiting a mid-type M dwarf ($M_\ast=0.36\pm0.02\ M_\odot$) every 4.34 days, accompanied by an associated white dwarf TOI-5628B ($M_{\rm WD}=0.59\pm0.16\ M_\odot$) at a projected distance of about 2,500 AU. Using TESS, ground-based photometry and SPIRou RVs, we constrain the planet radius to $0.74\pm0.04\ R_J$ and mass to $0.09\pm0.04\ M_J$, with a $3σ$ upper limit of $0.22\ M_J$. Building on this system, we further conduct a homogeneous systematic search for co-moving stellar companions with projected semi-major axis between 100 and 10,000 AU around all M dwarfs with confirmed giant planets with periods smaller than 10 days and radii larger than 0.7 $R_J$, as well as a group of field M stars with stellar properties similar to the planet sample, based on the stellar kinematics from Gaia DR3. We measure a stellar multiplicity of $34.2\pm9.5\%$ for M dwarfs hosting short-period giant planets, which is substantially higher than the fraction of $5.3\pm3.7\%$ for the field M stars by approximately a factor of 6. Our results suggest that wide-orbit stellar companions tend to promote the formation of short-period giant planets around M stars with masses $0.21 \leq M_\ast\leq 0.64\ M_\odot$, and high-eccentricity migration may play an important role in producing such systems. △ Less

Submitted 11 July, 2026; originally announced July 2026.

Comments: 20 pages, 7 figures, 3 tables, accepted for publication in ApJL

NGTS-39 b: A 58 d transiting warm Jupiter in an eccentric orbit

Authors: Ioannis Apergis, Daniel Bayliss, Solène Ulmer-Moll, Samuel Gill, Toby Rodel, Matthew Battley, Paul Benni, Allyson Bieryla, James A. Blake, Andrea Bonfanti, François Bouchy, Edward M. Bryant, Matthew R. Burleigh, Samuel J. Carlier, Sarah L. Casewell, Hritam Chakraborty, Alastair B. Claringbold, Karen A. Collins, Benjamin D. R. Davies, Xavier Dumusque, Troy A. Edkins, Fintan Eeles-Nolle, Jo Ann Egger, Jorge Fernández Fernández, Marcelo Aron Fetzner Keniger , et al. (31 additional authors not shown)

Abstract: We report the discovery and characterisation of NGTS-39 b (TIC 453147896 b), a warm Jupiter transiting a Sun-like star on a 58.2 day, eccentric (e = 0.386 +/- 0.019) orbit. NGTS-39 b was first identified from a TESS single-transit event, and subsequently confirmed with NGTS photometry and radial-velocity measurements from CORALIE and HARPS. The host star is a bright (Tmag = 11.02) F9 dwarf with an… ▽ More We report the discovery and characterisation of NGTS-39 b (TIC 453147896 b), a warm Jupiter transiting a Sun-like star on a 58.2 day, eccentric (e = 0.386 +/- 0.019) orbit. NGTS-39 b was first identified from a TESS single-transit event, and subsequently confirmed with NGTS photometry and radial-velocity measurements from CORALIE and HARPS. The host star is a bright (Tmag = 11.02) F9 dwarf with an effective temperature of Teff = 6053 +67/-30 K. NGTS-39 b is a Jupiter-sized gas giant with a radius of 1.088 +/- 0.012 RJ and a mass of 1.467 +/- 0.081 MJ. Its equilibrium temperature is 519 +6/-5 K, placing it between short-period hot Jupiters and cold, Jupiter-like giants. The high orbital eccentricity and intermediate equilibrium temperature of NGTS-39 b make it a valuable test case for formation and migration models, particularly in the poorly sampled regime of long-period gas giants. The RV data show a linear trend of gamma dot = -17.75 m s^-1 yr^-1, which indicates the presence of an outer companion. The discovery of NGTS-39 b contributes to the small but growing population of transiting warm Jupiters with P > 50 days orbiting bright stars. △ Less

Submitted 2 July, 2026; originally announced July 2026.

Comments: 16 pages, 11 figures, Accepted in Monthly Notices of the Royal Astronomical Society

The GAPS programme at TNG: LXXVI. TOI-1533: a compact system hosting a super-Neptune-mass pair with disparate radii

Authors: G. Mantovan, V. Nascimbeni, S. Desidera, L. Malavolta, J. J. Lissauer, P. Leonardi, T. Azevedo Silva, C. Guerra, D. Polychroni, L. Borsato, M. Baratella, K. Biazzo, D. Nardiello, K. A. Collins, M. Damasso, J. De Leon, M. E. Everett, D. Gandolfi, S. Giacalone, L. Naponiello, G. Piotto, G. Scandariato, K. Stassun, S. W. Yee, L. Affer , et al. (27 additional authors not shown)

Abstract: The present-day architecture of planetary systems contains information about their formation and migration histories. The origin of hot Jupiters (HJs, P $\lesssim$ 10 d, $R_{\rm p} > 8 R_\oplus$) has long been a matter of debate. While most of them are found to be ``lonely'', there is a rare population of HJs hosting small companions on inner orbits (eight known as of May 2026). Their peculiar arc… ▽ More The present-day architecture of planetary systems contains information about their formation and migration histories. The origin of hot Jupiters (HJs, P $\lesssim$ 10 d, $R_{\rm p} > 8 R_\oplus$) has long been a matter of debate. While most of them are found to be ``lonely'', there is a rare population of HJs hosting small companions on inner orbits (eight known as of May 2026). Their peculiar architecture suggests a gentle disc-migration mechanism. In this study, we present the discovery and characterisation of the multi-planet system TOI-1533, comprising an inner sub-Neptune (TOI-1533 b, $P_{\rm orb} = 3.63$ d, $R_{\rm p} = 3.15 R_\oplus$) and an outer hot giant planet (TOI-1533 c, $P_{\rm orb} = 8.06$ d, $R_{\rm p} > 7.5 R_\oplus$) with substantial H/He by mass ($ρ_{\rm p} < 0.48$ g cm$^{-3}$), both transiting an active K-dwarf star ($T_{\rm eff} \approx$ 5130 K; $V$ (mag) $\approx$ 11). Our joint modelling of stellar activity and planetary signals from radial velocities (HARPS-N) and transits (TESS) allows us to detect their Keplerian signals (approximately $10~σ$) and to isolate the stellar modulation. The inclusion of simultaneous photometry in the multi-dimensional Gaussian processes formalism was a fundamental addition to the spectroscopic activity indicators, enabling the disentanglement of stellar activity from planetary signals. The mass ratio of the two confirmed planets ($M_{\rm b} / M_{\rm c}$ about 0.8), together with the super-Neptune mass of the large outer companion ($M_{\rm c} \approx 40 M_\oplus$), makes this system unusual compared to the other few HJs with low-mass inner companions. △ Less

Submitted 17 July, 2026; v1 submitted 29 June, 2026; originally announced June 2026.

Comments: 19 pages, 22 figures, 5 tables. Accepted for publication in Astronomy & Astrophysics on 29 June 2026, first submission to A&A on 15 May

ASTEP confirmation of a pair of long-period Jupiter-sized planets with extremely low densities transiting TOI-791

Authors: Georgina Dransfield, Antoine C. Petit, Amaury H. M. J. Triaud, Tristan Guillot, François-Xavier Schmider, Lyu Abe, Abdelkrim Agabi, Khalid Barkaoui, Thomas A. Baycroft, Philippe Bendjoya, Rafael Brahm, Karen A. Collins, Billy Edwards, Phil Evans, Alix V. Freckelton, Nolan Grieves, Steve B. Howell, Franco Mallia, Djamel Mekarnia, Angelica Psaridi, Daniel Sebastian, Keivan G. Stassun, Chris Stockdale, Amalie Stokholm, Olga Suarez , et al. (23 additional authors not shown)

Abstract: Gas giant planets with periods $20~<~P~<~300~\rm days$ orbiting Sun-like stars are a relatively uncommon outcome of planetary formation, and key questions about the nature and formation of this sub-population remain unanswered. Theoretical models for the location of their formation (in- or ex-situ) and for their subsequent migration predict different outcomes in terms of planet masses and eccentri… ▽ More Gas giant planets with periods $20~<~P~<~300~\rm days$ orbiting Sun-like stars are a relatively uncommon outcome of planetary formation, and key questions about the nature and formation of this sub-population remain unanswered. Theoretical models for the location of their formation (in- or ex-situ) and for their subsequent migration predict different outcomes in terms of planet masses and eccentricities, indicating that observations have a key role to play in disentangling their histories. In this work we present the discovery and confirmation of a pair of long-period Jupiter-sized planets transiting an F7 star: TOI-791 b is a $0.993\pm0.033\rm~R_{Jup}$ planet on a $139.29931_{-0.00012}^{+0.00011}~\rm day$ orbit, and TOI-791 c, a $1.155\pm0.040\rm ~R_{Jup}$ planet on a $232.01570_{-0.00071}^{+0.00067}~\rm day$ orbit. The two planets are within 0.07% of a second-order 5:3 period commensurability leading to transit timing variations (TTVs) of up to 50 minutes. We confirm their planetary nature using ground-based photometry, including multiple full detections of the $>11~\rm hr$ transits of both TOI-791 b and c from Antarctica with ASTEP, making these the longest-duration transits ever observed in their entirety from the ground. Our detailed analysis of the TTV signal allows us to measure dynamical masses for both planets, which yield densities of $ρ_{\rm b}=0.038\pm0.008 \rm ~g~cm^{-3}$ and $ρ_{\rm c}=0.047\pm0.006 \rm ~g~cm^{-3}$, indicating that TOI-791~b and c are two of the lowest density giant planets ever detected. While these measurements are robust, further follow-up is needed to fully characterise the TTV signal and the architecture of the system. △ Less

Submitted 29 June, 2026; originally announced June 2026.

Comments: 22 pages, 18 figures, Published in MNRAS

Journal ref: Monthly Notices of the Royal Astronomical Society, Volume 549, Issue 4, July 2026, stag864

TOI-6884b: A low-mass brown dwarf transiting a slightly evolved star

Authors: Akanksha Khandelwal, Shubhendra Nath Das, Rishikesh Sharma, Abhijit Chakraborty, Churchil Dwivedi, Sanjay Baliwal, Karen A. Collins, David W. Latham, Allyson Bieryla, Cristilyn N. Watkins, Felipe Murgas, Norio Narita, Enric Palle, Steve B. Howell, Mark E. Everett, Catherine A. Clark, Polina A. Budnikova, David Ciardi, Nikitha Jithendran, Akihiko Fukui, Ashirbad Nayak, Bob Massey, Boris Safonov, Florence Libotte, Francis P. Wilkin , et al. (20 additional authors not shown)

Abstract: We report the discovery of a low-mass transiting brown dwarf orbiting TOI-6884 (TIC~156514476, $T_{\rm mag}=11.4$) from NASA's \textit{Transiting Exoplanet Survey Satellite} (\textit{TESS}) mission. The \textit{TESS} light curves initially suggested an orbital period of $\sim$14.42~days; however, our high-precision ground-based radial velocity measurements and multi-epoch time-series photometry re… ▽ More We report the discovery of a low-mass transiting brown dwarf orbiting TOI-6884 (TIC~156514476, $T_{\rm mag}=11.4$) from NASA's \textit{Transiting Exoplanet Survey Satellite} (\textit{TESS}) mission. The \textit{TESS} light curves initially suggested an orbital period of $\sim$14.42~days; however, our high-precision ground-based radial velocity measurements and multi-epoch time-series photometry reveal this to be a harmonic alias. We determine the true orbital period to be $4.808264^{+0.000015}_{-0.000014}$~days and confirm the substellar nature of the companion. TOI-6884b has a mass of $26.32^{+0.98}_{-0.93}\,M_{\mathrm{J}}$, a radius of $0.927^{+0.51}_{-0.52}\,R_{\mathrm{J}}$, and resides on a nearly circular orbit ($e=0.067^{+0.010}_{-0.012}$). Its host star is a late F-type slightly evolved star with $M_\star = 1.410^{+0.075}_{-0.069}\,M_\odot$,\msun, $R_\star = 1.840^{+0.072}_{-0.073}\,R_\odot$, $\log{g} = 4.057^{+0.045}_{-0.039}$, $[{\rm Fe/H}] = 0.094^{+0.073}_{-0.068}$~dex, and $T_{\rm eff}=6330^{+180}_{-160}$,\mathrm{K}$. TOI-6884b is a key addition to the small population of well-characterized transiting brown dwarfs orbiting host stars that have evolved off the main sequence. The detection of such systems will contribute to our understanding of the dynamical histories and structural evolution of short-period substellar companions around evolved stars. △ Less

Submitted 28 June, 2026; originally announced June 2026.

Comments: 18 pages, 14 figures

Observing a 542-day transiting giant with large TTVs: The 2025 transit of HIP 41378 f and new constraints on the outer system

Authors: Pietro Leonardi, Alexandre Santerne, Luca Borsato, Salomé Grouffal, Christopher R. Mann, Giampaolo Piotto, Karen A. Collins, Patrick Tamburo, Yugo Kawai, Denise C. Stephens, Juliana García-Mejía, Edward M. Bryant, Krzysztof Sz. Zielinski, Daniel Bayliss, David Charbonneau, Jerome P. de Leon, Gareb Fernández-Rodríguez, Akihiko Fukui, Eric G. Hintz, Keith Horne, Keisuke Isogai, James S. Jenkins, Norio Narita, Ramotholo Sefako, Avi Shporer , et al. (5 additional authors not shown)

Abstract: Characterizing long-period transiting exoplanets is inherently challenging due to the rarity and long duration of transit events. Yet, these systems provide unique insights into planetary formation, migration, the detection of exomoons, and primordial atmospheres by occupying a sparsely populated region of the exoplanet parameter space. The complexity increases further for long-period planets near… ▽ More Characterizing long-period transiting exoplanets is inherently challenging due to the rarity and long duration of transit events. Yet, these systems provide unique insights into planetary formation, migration, the detection of exomoons, and primordial atmospheres by occupying a sparsely populated region of the exoplanet parameter space. The complexity increases further for long-period planets near mean-motion resonances, where transit timing variations (TTVs) can reach amplitudes of several hours to days. We present a coordinated space- and ground-based observing campaign, using photometry from NEOSSat, multiple LCOGT sites, MuSCAT, MuSCAT3, Tierras and NGTS, to capture the 19-hour transit of the long-period giant exoplanet HIP 41378 f ($P$ = 542 d, $R$ = 9.5 $R_{\oplus}$) on 31 October 2025. Our transit analysis constrains the time of inferior conjunction to $T_{\mathrm{C}} = 2460980.888 \pm 0.029~\mathrm{BJD_{TDB}}$, occurring $\sim 7$ hours earlier than predicted from its linear ephemeris. This significant offset is consistent with the previously reported TTVs of HIP 41378 f, making it the longest-period exoplanet known to exhibit measurable TTVs. By combining this new precise measurement to the transit timings of the two outer planets in the system (HIP 41378 d and HIP 41378 e), we perform a dynamical modeling of the system, using the N-body integrator TRADES, refine the ephemeris of HIP 41378 f, and predict future transit events for all three outer transiting planets. △ Less

Submitted 27 June, 2026; v1 submitted 22 June, 2026; originally announced June 2026.

Comments: 14 pages, 10 figures. Accepted for publication in Astronomy & Astrophysics. This manuscript is complementary to the paper by Grouffal et al. (2026, A&A), entitled "A decade of monitoring the HIP 41378 planetary system: masses and orbital periods of the six planets and an additional planet candidate."

Transmission Zero Forcing

Authors: Adam H. Berliner, Chassidy Bozeman, Karen L. Collins, Mary Flagg, Veronika Furst, Mark Hunnell

Abstract: We initiate the study of transmission zero forcing, a variant of the well-studied zero forcing graph parameter. In this variant, a subset of vertices is assigned an initial unit weight, and these vertices can increase the weight of a neighbor subject to the zero forcing color change rule at a rate determined by the transmission proportion. A vertex is considered filled when its weight exceeds the… ▽ More We initiate the study of transmission zero forcing, a variant of the well-studied zero forcing graph parameter. In this variant, a subset of vertices is assigned an initial unit weight, and these vertices can increase the weight of a neighbor subject to the zero forcing color change rule at a rate determined by the transmission proportion. A vertex is considered filled when its weight exceeds the transmission threshold, at which point the process can continue. The transmission zero forcing number of a graph is the minimum cardinality of the initial set that results in all vertices exceeding the transmission threshold. This iterative graph coloring process is a generalization of zero forcing that allows for a vertex to be forced by multiple neighbors. We develop tools for studying this graph parameter, determine its value on some common classes of graphs, and investigate its behavior under various graph operations. △ Less

Submitted 27 June, 2026; v1 submitted 20 June, 2026; originally announced June 2026.

MSC Class: 05C69 05C57 05C38

TOI-2147 b and TOI-6019 b: Two eccentric warm Jupiters detected and characterized with TESS and MaHPS

Authors: Luis Thomas, Louise D. Nielsen, Hanna Kellermann, Bibiana Prinoth, Yutong Liu, Elif Zeynep Özden, Arno Riffeser, Claus Gössl, Frank Grupp, Jerome de Leon, Karen A. Collins, Allyson Bieryla, Lorena Acuña-Aguirre, Keith Baka, Malte Busmann, David R. Ciardi, Catherine A. Clark, Juliana Ehrhardt, Mark E. Everett, Akihiko Fukui, Jan-Vincent Harre, Keisuke Isogai, Yanxi Li, Felipe Murgas, Norio Narita , et al. (14 additional authors not shown)

Abstract: The population of Jupiter-sized exoplanets with orbital periods between 10 and 200 days (WJs) exhibits a broad range of orbital eccentricities and system architectures, suggesting a diversity of formation and migration pathways. In this work, we report the detection and characterization of two new eccentric WJs, TOI-2147 b and TOI-6019 b, initially identified as planet candidates by the Transiting… ▽ More The population of Jupiter-sized exoplanets with orbital periods between 10 and 200 days (WJs) exhibits a broad range of orbital eccentricities and system architectures, suggesting a diversity of formation and migration pathways. In this work, we report the detection and characterization of two new eccentric WJs, TOI-2147 b and TOI-6019 b, initially identified as planet candidates by the Transiting Exoplanet Survey Satellite (TESS). We combined TESS photometry with ground-based follow-up observations, including multiband photometry from LCOGT and MuSCAT2, high-angular-resolution speckle imaging, and high-precision radial velocity measurements from the high-resolution Manfred Hirt Planet Finder Spectrograph (MaHPS). Using these data, we were able to confirm the planetary nature of both candidates. TOI-2147 b has a radius of $10.5 \pm 0.3\,\mathrm{R}_\oplus$ and a mass of $116 \pm 22\,\mathrm{M}_\oplus$. It orbits its slightly metal-poor ($\mathrm{[Fe/H]} = -0.29^{+0.07}_{-0.08}$) G-type host star on an eccentric orbit ($e = 0.29 \pm 0.07$) with a period of 26.2 days. TOI-6019 b has a radius of $12.3 \pm 0.3\,\mathrm{R}_\oplus$ and a mass of $149 \pm 15\,\mathrm{M}_\oplus$. It orbits a slightly evolved, solar-metallicity G-type sub-giant with a period of 14.5 days on a significantly eccentric orbit ($e = 0.48^{+0.05}_{-0.04}$). Both planets have bulk densities below that of Jupiter, indicating mildly inflated radii, with interior structure modeling using GASTLI. This suggests that tidal heating from the nonzero eccentricities likely contributes to this inflation and disfavors large atmospheric metal enrichment. No significant signals from additional companions were detected in the radial velocity time series or transit timing variations. Together with the elevated eccentricities, this is consistent with a high-eccentricity migration origin for both systems. △ Less

Submitted 10 August, 2026; v1 submitted 18 June, 2026; originally announced June 2026.

Comments: 14 pages, 9 figures. Accepted for publication in A&A

Revisiting the Exo-Mercury Candidate GJ 367 b with ESPRESSO and a Self-Consistent Tidal Distortion Model

Authors: Rena A. Lee, Fei Dai, Ellen M. Price, Te Han, Davide Gandolfi, Mathias Zechmeister, Guðmundur Stefánsson, Jiayin Dong, Simon H. Albrecht, Kristine W. F. Lam, Federica Chiti, Jennifer L. van Saders, Daniel Huber, Heather A. Knutson, Karen A. Collins, Michael Zhang, Leslie A. Rogers, Eleonora Armano, Casey L. Brinkman, Nicholas Saunders, Daniel Hey

Abstract: We report revised mass and radius measurements for GJ 367 b, an ultra-short-period (7.7 hr) sub-Earth in a multi-planet system orbiting a nearby (~9 pc) M dwarf host. Previous mass and radius measurements have suggested GJ 367 b has an anomalously high bulk density, close to that of solid iron. The existence of such an iron-rich planet is in tension with established planet formation scenarios. We… ▽ More We report revised mass and radius measurements for GJ 367 b, an ultra-short-period (7.7 hr) sub-Earth in a multi-planet system orbiting a nearby (~9 pc) M dwarf host. Previous mass and radius measurements have suggested GJ 367 b has an anomalously high bulk density, close to that of solid iron. The existence of such an iron-rich planet is in tension with established planet formation scenarios. We utilized newly available TESS short-cadence photometry to constrain the radius of GJ 367 b to 0.736 +/- 0.035 R_Earth. We consider observational and modeling effects such as photometric dilution, stellar activity, and tidal distortion to account for possible inaccuracies in the star and planet radius measurements. From our radial velocity (RV) analysis using VLT/ESPRESSO data covering nearly the full orbit in a single night, we find a mass of 0.503 +/- 0.078 M_Earth, corresponding to a bulk density of 6.9 +1.6/-1.4 g cm-1. We present a new tidal distortion and interior composition modeling framework to assess the iron mass fraction of GJ 367 b. Considering several different interior composition assumptions and radial aspect ratios, we find an iron fraction of ~50-70%, which is broadly consistent with that of Mercury and not as iron rich as previously suggested. △ Less

Submitted 16 June, 2026; originally announced June 2026.

Comments: accepted to ApJ

Stellar Obliquities of Young Systems, Atmospheres Undergoing Contraction and Escape (SOYSAUCE) II: a 135 Myr planet on an aligned orbit with transit timing variations

Authors: Madyson G. Barber, Andrew W. Mann, Sydney Vach, Leah J. Boff, Andrew W. Boyle, Andrew Vanderburg, Adam L. Kraus, Benjamin M. Tofflemire, Marshall C. Johnson, Allyson Bieryla, David W. Latham, Karen A. Collins, Steve B. Howell, Richard P. Schwarz, Gregorg Srdoc, Francis P. Wilkin, Felipe Murgas, Enric Palle, Chris Stockdale

Abstract: Young planets (<1 Gyr) provide opportunities to directly probe planet formation and evolution processes in action. However, due to heightened stellar activity, there is a lack of known transiting planets in adolescence (~100-500 Myr). Here we present the validation of TIC 150070085 b, a 3.6 R_E planet on a 10.47 day orbit, and report the candidate TIC 150070085 c, a 3.0 R_E planet on a 15.90 day o… ▽ More Young planets (<1 Gyr) provide opportunities to directly probe planet formation and evolution processes in action. However, due to heightened stellar activity, there is a lack of known transiting planets in adolescence (~100-500 Myr). Here we present the validation of TIC 150070085 b, a 3.6 R_E planet on a 10.47 day orbit, and report the candidate TIC 150070085 c, a 3.0 R_E planet on a 15.90 day orbit. While we are unable to validate the second signal, the proximity to mean motion resonance (3:2) and transit timing variations observed in the transits of TIC 150070085 b strongly suggest the signal is planetary. We confirm the host star as a member of Alessi 84 and combine the group's CMD, rotation, and variability properties to update the age to 135 +/- 10 Myr. We additionally use MAROON-X to observe the Rossiter-McLaughlin signal of TIC 150070085 b and measure the sky projected obliquity angle ($λ$). We find TIC 150070085 b is consistent with a near-aligned orbit with its host star (|$λ$| = 18 +/- 12$^\circ$), in line with similarly aged transiting planets with measured $λ$ values. Continued discovery and characterization of planets in this age regime are vital to link planetary infancy (<50 Myr) and maturity (>1 Gyr). △ Less

Submitted 8 June, 2026; originally announced June 2026.

Comments: Accepted for publication in the Journals of the AAS

Discrete-time treatment number of binary trees

Authors: Karen L. Collins, Margaret-Ellen Messinger, Ann N. Trenk

Abstract: The discrete-time treatment number of a graph $H$, denoted by $τ(H)$, was introduced in arXiv:2408.0531(3) and arises from a deterministic process in which each vertex is assigned a color at each time-step. The pathwidth upper bound $τ(H)\leq \lceil\frac{1+pw(H)}{2}\rceil$, is shown in arXiv:2408.0531(3), where $pw(H)$ denotes the pathwidth of graph $H$. Equality holds when $H$ is the complete bin… ▽ More The discrete-time treatment number of a graph $H$, denoted by $τ(H)$, was introduced in arXiv:2408.0531(3) and arises from a deterministic process in which each vertex is assigned a color at each time-step. The pathwidth upper bound $τ(H)\leq \lceil\frac{1+pw(H)}{2}\rceil$, is shown in arXiv:2408.0531(3), where $pw(H)$ denotes the pathwidth of graph $H$. Equality holds when $H$ is the complete binary tree of depth $d$ (denoted by $BT(d)$) and $1 \le d \le 6$. In this paper, we characterize the sizes of all subsets of vertices of $BT(d)$ whose boundary has $3$ or fewer vertices and use this result to prove that $τ(BT(d))= 3$ for $8\leq d\leq 10$; in these cases, equality also holds in the pathwidth upper bound. By the hereditary property of the treatment number, all larger complete binary trees have treatment number at least $3$. In contrast, we provide an explicit construction to show that $τ(BT(7))=2$, while the pathwidth upper bound only shows $τ(BT(7))\le 3.$ We construct an infinite family of graphs, each with a cut-vertex, whose treatment number depends on the number of components when the cut-vertex is removed. We use a combination of pathwidth and vertex cuts to prove another upper bound on the treatment number and use this to construct an infinite family of graphs whose boundary size is limited, but whose treatment number is unlimited. △ Less

Submitted 6 June, 2026; originally announced June 2026.

Comments: 22 pages, 7 figures

MSC Class: O5C57

Analyzing spatial point processes degraded by displacement and imperfect detection

Authors: Kevin M. Collins, Erin M. Schliep, Alan E. Gelfand, Tina M. Yack, Christopher W. Clark, Robert S. Schick

Abstract: Spatial point processes are a valuable tool for probabilistic modeling to explain location data. However, the data themselves are often observed imperfectly. In order to perform accurate inference, one must account for these imperfections, which we refer to as degradation. We consider two forms of degradation for spatial Poisson processes: thinning and displacement. First, we provide some theoreti… ▽ More Spatial point processes are a valuable tool for probabilistic modeling to explain location data. However, the data themselves are often observed imperfectly. In order to perform accurate inference, one must account for these imperfections, which we refer to as degradation. We consider two forms of degradation for spatial Poisson processes: thinning and displacement. First, we provide some theoretical results on model identifiability, showing that, under weak conditions, one can jointly learn the scale of the displacement, a parametric form of thinning, and a nonparametric intensity function. The ability to learn all of these components and the resulting improvements for inference compared to the conceptual non-degraded but misspecified model are shown empirically via simulation study. Finally, we apply this approach to North Atlantic right whale call data from Cape Cod Bay. △ Less

Submitted 3 June, 2026; originally announced June 2026.

Human agency in initial human-AI proof formalization workflows

Authors: Katherine M. Collins, Simon Frieder, Jonas Bayer, Jacob Loader, Jeck Lim, Peiyang Song, Fabian Zaiser, Lexin Zhou, Shanda Li, Sam Looi, Joshua B. Tenenbaum, Umang Bhatt, Adrian Weller, Jose Hernandez-Orallo, Cameron E. Freer, Valerie Chen, Ilia Sucholutsky

Abstract: For centuries, human mathematicians have written proofs to substantiate their mathematical arguments; yet, the ability to automatically verify the validity of proofs has long been a challenge. Advances in AI systems' ability to generate code and engage in increasingly high-level mathematical reasoning promise to transform people's ability to formalize and thereby verify proofs. While many works fo… ▽ More For centuries, human mathematicians have written proofs to substantiate their mathematical arguments; yet, the ability to automatically verify the validity of proofs has long been a challenge. Advances in AI systems' ability to generate code and engage in increasingly high-level mathematical reasoning promise to transform people's ability to formalize and thereby verify proofs. While many works focus on benchmarking the current frontier, we instead study how people use these tools and apply agency in doing so. We conduct a mixed-methods analysis into the initial impact of AI on people's formalization workflows: what people claim they want, what they see as the barriers to those visions, and how they actually use and adapt AI in practice. A qualitative survey reveals that people's preferences are diverse, but with a general desire for AI assistance in formalization that preserves high-level human control and agency over the proof discovery process. To assess how people actually engage with AI for formalization, we conduct a controlled user study in which participants formalize informal math problems and their proofs, with and without AI, across a range of mathematical problems at varying levels of difficulty and domains. Despite limitations of the tools at the time for autoformalization, participants tended to attain higher formalization accuracy when allowed access to AI tools than when formalizing on their own, with most participants flexibly choosing to use multiple different AI tools. Taken together, our work sheds light on the early stages of AI integration into formalization workflows, involving an intimate interplay of human agency and AI engagement. △ Less

Submitted 7 August, 2026; v1 submitted 2 June, 2026; originally announced June 2026.

Comments: Updated working paper

Cognitive offloading and the speedup illusion in human-AI interaction

Authors: Sunny Yu, Myra Cheng, Ahmad Jabbar, Ilia Sucholutsky, Katherine M. Collins, Dan Jurafsky, Robert D. Hawkins

Abstract: Large language models (LLMs) have the potential to boost human productivity by speeding up task completion -- provided users know when to offload cognitive work to them. But we do not know if users are well-calibrated in estimating these potential time savings. We conducted a preregistered large-scale behavioral study (N = 1237) to characterize mismatches between expectations and reality, with a f… ▽ More Large language models (LLMs) have the potential to boost human productivity by speeding up task completion -- provided users know when to offload cognitive work to them. But we do not know if users are well-calibrated in estimating these potential time savings. We conducted a preregistered large-scale behavioral study (N = 1237) to characterize mismatches between expectations and reality, with a focus on simple cognitive tasks. While actual completion times between independent completion and AI-assisted completion did not differ, participants predicted AI to be significantly faster. The same bias was not observed when imagining help from another human participant. We identify a speedup illusion where people have accurate forecasts of independent completion times but significantly underestimate AI-assisted times. Additionally, time and effort dissociate: participants reported lower subjective effort with AI despite equivalent completion times. This suggests that completion time itself is not sufficient to characterize efficiency gains. △ Less

Submitted 21 May, 2026; originally announced May 2026.

Comments: Proceedings of the 48th Annual Meeting of the Cognitive Science Society

The efficiency-gain illusion: People underestimate the rate of AI use and overestimate its benefits on simple tasks

Authors: Sunny Yu, Myra Cheng, Ahmad Jabbar, Ilia Sucholutsky, Katherine M. Collins, Dan Jurafsky, Robert D. Hawkins

Abstract: People are increasingly turning to AI assistance for simple tasks, e.g., arithmetic, spell-check, and answering simple questions. But does AI assistance actually save users time and effort? We investigate people's propensity to use AI for cognitively simple tasks and assess whether their reliance is well-calibrated. Across three pre-registered user studies (N = 2691), we find that people frequentl… ▽ More People are increasingly turning to AI assistance for simple tasks, e.g., arithmetic, spell-check, and answering simple questions. But does AI assistance actually save users time and effort? We investigate people's propensity to use AI for cognitively simple tasks and assess whether their reliance is well-calibrated. Across three pre-registered user studies (N = 2691), we find that people frequently choose to use AI even when doing so is inefficient (i.e. provides no meaningful time or effort savings). We identify systematic miscalibration at two levels: (1) a self-estimate miscalibration where people on average believe that they are using AI less than they actually are, and (2) efficiency-gain illusions where people overestimate how much time and effort savings AI use affords. We also identify a session-level carryover effect where a participant's prior AI use leads to further AI adoption and entrenches their miscalibration about time savings. Our results shed light on the mechanisms and biases underlying people's choice of whether to use AI as well as the risk of an overreliance feedback loop. △ Less

Submitted 21 May, 2026; originally announced May 2026.

Medical Model Synthesis Architectures: A Case Study

Authors: Katherine M. Collins, Marlene Berke, Ilia Sucholutsky, Ayman Ali, Adrian Weller, Timothy J. O'Donnell, Tyler Brooke-Wilson, Lionel Wong, Joshua B. Tenenbaum

Abstract: Medicine is rife with high-stakes uncertainty. Doctors routinely make clinical judgments and decisions that juggle many fundamental unknowns, like predictions about what might be causing a patients' symptoms or decisions about what treatment to try next. Despite increasing interest in developing AI systems that aid or even replace doctors in clinical settings, current systems struggle with calibra… ▽ More Medicine is rife with high-stakes uncertainty. Doctors routinely make clinical judgments and decisions that juggle many fundamental unknowns, like predictions about what might be causing a patients' symptoms or decisions about what treatment to try next. Despite increasing interest in developing AI systems that aid or even replace doctors in clinical settings, current systems struggle with calibrated reasoning under uncertainty, and are often deeply opaque about their reasoning. We propose a framework for AI systems that can make practically useful but formally transparent clinical predictions under uncertainty. Given a clinical situation, our framework (MedMSA) uses language models to retrieve relevant prior knowledge, but constructs a formal probabilistic model to support calibrated and verifiable inferences under uncertainty. We show how an initial proof-of-concept of this framework can be used for differential diagnosis, producing an uncertainty-weighted list of potential diagnoses that could explain a patients' symptoms, and discuss future applications and directions for applying this framework more generally for safe clinical collaborations. △ Less

Submitted 10 May, 2026; originally announced May 2026.

Comments: Working paper

Accounting for variable detection functions in temporal abundance modeling via transfer learning

Authors: Kevin M. Collins, Erin M. Schliep, Tyler Wagner, Christopher K. Wikle

Abstract: Relative abundance, measured as the number of animals caught per unit of sampling effort (CPUE), is commonly used to monitor fish and wildlife populations, largely because sampling methods are cost-effective to implement. Modeling relative abundance, however, requires the assumption that the detection probability is constant across sampling events. This assumption is likely not valid, as the proba… ▽ More Relative abundance, measured as the number of animals caught per unit of sampling effort (CPUE), is commonly used to monitor fish and wildlife populations, largely because sampling methods are cost-effective to implement. Modeling relative abundance, however, requires the assumption that the detection probability is constant across sampling events. This assumption is likely not valid, as the probability of detection often varies as a function of several factors, including the characteristics of individual animals and environmental conditions at the time of sampling. In contrast, methods to estimate absolute abundance, such as capture-recapture (CR), account for variable detection, but are often infeasible to implement across large spatiotemporal scales. Despite this, CR data are sometimes available for species of interest, albeit at smaller spatiotemporal extents. Leveraging information on detection probabilities from CR data to help inform estimates of widely available CPUE data could strengthen inferences about the status of fish and wildlife populations. We propose an approach to (i) learn the effect of environmental covariates on detection probabilities from CR data and (ii) transfer these detection functions to CPUE models for improved inference. Shown empirically through a simulation study, this approach improves estimates of abundance and the ability to detect temporal trends. We apply our transfer learning method using CR and CPUE data to recreationally important smallmouth bass (\textit{Micropterus dolomieu}) fisheries in Pennsylvania, USA rivers. △ Less

Submitted 8 May, 2026; originally announced May 2026.

Improving the Efficiency of Language Agent Teams with Adaptive Task Graphs

Authors: Elizabeth Mieczkowski, Alexander Ku, Tiwalayo Eisape, Dilip Arumugam, John Matters, Katherine M. Collins, Ilia Sucholutsky, Thomas L. Griffiths

Abstract: Large language models (LLMs) are increasingly deployed in teams, yet existing coordination approaches often occupy two extremes. Highly structured methods rely on fixed roles, pipelines, or task decompositions assigned a priori. In contrast, fully unstructured teams enable adaptability and exploration but suffer from inefficiencies such as error propagation, inter-agent conflicts, and wasted resou… ▽ More Large language models (LLMs) are increasingly deployed in teams, yet existing coordination approaches often occupy two extremes. Highly structured methods rely on fixed roles, pipelines, or task decompositions assigned a priori. In contrast, fully unstructured teams enable adaptability and exploration but suffer from inefficiencies such as error propagation, inter-agent conflicts, and wasted resources (measured in time, tokens, or file operations). We introduce Language Agent Teams for Task Evolution (LATTE), a framework for coordinating LLM teams inspired by distributed systems, where processors must operate under partial observability and communication constraints. In LATTE, a team of agents collaboratively construct and maintain a shared, evolving coordination graph which encodes sub-task dependencies, individual agent assignment, and the current state of sub-task progress. This protocol maintains consistency while empowering agents to dynamically allocate work, adapt coordination, and discover new tasks. Across multiple collaborative tasks and a variety of base models, we demonstrate how LATTE reduces token usage, wall-clock time, communication, and coordination failures (e.g. file conflicts and redundant outputs) while matching or exceeding the accuracy of standard designs including MetaGPT, decentralized teams, top-down Leader-Worker hierarchies, and static decompositions. △ Less

Submitted 7 May, 2026; originally announced May 2026.

TOI-159 b: an eccentric hot-Jupiter planet around a young, pulsating $γ$ Doradus star

Authors: G. Mantovan, A. Llancaqueo Albornoz, A. Psaridi, A. Thompson, T. Zingales, V. Nascimbeni, S. Villanova, G. Piotto, K. A. Collins, J. Serna, L. Malavolta, K. Stassun, F. Bouchy, C. C. Cortes, P. Evans, T. Gan, M. Lendl, M. B. Lund, D. Nardiello

Abstract: Fast-rotating hot stars are challenging targets for exoplanet searches due to rotational broadening and stellar variability. Moreover, hot stars often exhibit pulsations, an additional source of scatter in both photometric and spectroscopic series. Because of these challenges, such stars remain a relatively unexplored environment for planetary architecture and evolution studies. In this study, we… ▽ More Fast-rotating hot stars are challenging targets for exoplanet searches due to rotational broadening and stellar variability. Moreover, hot stars often exhibit pulsations, an additional source of scatter in both photometric and spectroscopic series. Because of these challenges, such stars remain a relatively unexplored environment for planetary architecture and evolution studies. In this study, we present the confirmation and preliminary atmospheric characterisation of a giant planet orbiting a young ($\approx$ 150 Myr), pulsating $γ$ Doradus star. TOI-159 b ($P_{\rm orb} \simeq 3.7$ d, $R_{\rm p} \simeq 1.6~R_{\rm J}$, $M_{\rm p} \simeq 3.5 M_{\rm J}$) is an S-type planet in a close binary system and is the hottest ($T_{\rm eq} \simeq 1900$ K) hot Jupiter with a significant eccentricity ($e = 0.24 \pm 0.04$) ever detected. Our joint modelling of radial velocities (HARPS and CORALIE), transits (\textit{TESS}), and spectro-photometry (IMACS) allows us to detect its Keplerian signal at high significance ($13 σ$), place strong constraints on its eccentricity ($6 σ$), disentangle the stellar rotational modulation and pulsation periods, and generate a low-resolution transmission spectrum, on which we conduct an exploratory analysis to constrain the presence of a planetary atmosphere using combined star-planet retrievals. Whilst our spectrum appears to display some modulation, the data is too coarse to allow for any conclusive detections at this stage. Higher-resolution observations are needed to confirm or refute these features and, if genuine, determine whether they originate from contamination from the star or a planetary atmosphere. △ Less

Submitted 5 May, 2026; originally announced May 2026.

Comments: 19 pages, 20 figures, 6 tables. Accepted for publication in Astronomy & Astrophysics on 5 May 2026, first submission to A&A on 6 February 2026

RV and TTV Measurements of Two Transiting Long-Period Giants around TOI-4600

Authors: Tong Hu, Zitao Lin, Sharon X. Wang, Mu-Tian Wang, Ismael Mireles, Jacob Bean, Madison Brady, Nina Brown, Qikang Feng, Tianjun Gan, Chengyang Ji, Xue Li, Jiayue Zhang, Ritvik Basant, Nikita Chazov, David Charbonneau, Karen A. Collins, Tanya Das, Diana Dragomir, Zahra Essack, Juliana Garcia-Mejia, Yang Huang, Jinzhong Liu, Christopher R. Mann, Hugh P. Osborn , et al. (5 additional authors not shown)

Abstract: TOI-4600b and c, originally identified by the Transiting Exoplanet Survey Satellite (TESS) and reported by I. Mireles et al. (2023), are a rare pair of transiting long-period giant planets ($\rm P_b=82.7$ days, $\rm P_c=482.8$ days) orbiting an early K dwarf. In this work, we refine the orbital parameters of the TOI-4600 system by combining new TESS photometry, ground-based transit follow-up, and… ▽ More TOI-4600b and c, originally identified by the Transiting Exoplanet Survey Satellite (TESS) and reported by I. Mireles et al. (2023), are a rare pair of transiting long-period giant planets ($\rm P_b=82.7$ days, $\rm P_c=482.8$ days) orbiting an early K dwarf. In this work, we refine the orbital parameters of the TOI-4600 system by combining new TESS photometry, ground-based transit follow-up, and radial velocity (RV) observations from MAROON-X. We obtain improved constraints on planetary masses and eccentricities, and update other parameters, such as the stellar age. For TOI-4600b, we measure a mass of $M_p = 74.7^{+4.7}_{-4.4}\,M_{\oplus}$ and an eccentricity of $e=0.153^{+0.020}_{-0.018}$, and $M_p = 212.53^{+13.26}_{-13.03}\,M_{\oplus}$ and $e=0.219^{+0.015}_{-0.018}$ for TOI-4600c. We find significant transit timing variations (TTV) in both planets, with semi-amplitudes of approximately $1$\,hr. We derive Transit Spectroscopy Metric values of 16.87 for TOI-4600b and 10.09 for TOI-4600c, indicating that both planets are promising JWST targets for studying the atmospheres of temperate and cold Jupiters, a relatively poorly characterized sample thus far. These updated parameters and TTV ephemerides are important for planning and interpreting future photometric, spectroscopic, and dynamical studies of the TOI-4600 system. △ Less

Submitted 29 April, 2026; originally announced April 2026.

Comments: Submitted to AJ, 23 pages, 6 figures, 7 tables

Uncovering the Rapidly Evolving Orbits of the Dynamic TOI-201 System

Authors: Ismael Mireles, Solène Ulmer-Moll, Donald Liveoak, Diana Dragomir, Judith Korth, Alexander Venner, Karen A. Collins, Amaury H. M. J. Triaud, Tristan Guillot, Antoine Petit, Theron Carmichael, Sarah Millholland, Tim Hallatt, Hannu Parviainen, Hugh P. Osborn, David Rapetti, Thomas A. Baycroft, Siddharth Bhatnagar, François Bouchy, Radka Dancikova, Pedro Figueira, Monika Lendl, Stéphane Udry, Peter Wheatley, Lyu Abe , et al. (25 additional authors not shown)

Abstract: Studying planetary interactions in exoplanet systems informs theories of planet formation and evolution, providing essential context for understanding our own solar system. We combine spectroscopy, transit photometry, transit timing variations, and astrometry to characterize the TOI-201 system. The co-transiting system consists of a super-Earth, warm Jupiter, and massive companion at 5.8, 53, and… ▽ More Studying planetary interactions in exoplanet systems informs theories of planet formation and evolution, providing essential context for understanding our own solar system. We combine spectroscopy, transit photometry, transit timing variations, and astrometry to characterize the TOI-201 system. The co-transiting system consists of a super-Earth, warm Jupiter, and massive companion at 5.8, 53, and 2900 day orbital periods, respectively. We perform dynamical simulations to study the past and future of the system. von-Zeipel-Kozai-Lidov oscillations emerge as the most plausible scenario to explain the outer companion's high orbital eccentricity, with planet-planet scattering a possible but less likely contender. Due to non-zero mutual inclinations between the planets, the system is visibly evolving on very short timescales, with the current co-transiting configuration ending in 200 years. △ Less

Submitted 26 April, 2026; originally announced April 2026.

Comments: Published in Science Advances

Journal ref: Science Advances, 12, 16, eaef2618, 2026

A gem system with a lava world and a habitable zone sub-Neptune orbiting TOI-1752

Authors: A. Peláez-Torres, F. J. Pozuelos, G. Morello, M. Dévora-Pajares, K. Barkaoui, L. Gkouvelis, E. Pallé, K. A. Collins, B. V. Rackham, S. Geraldía-González, M. Centenera-Merino, R. Varas, E. Esparza-Borges, Z. Parlapani, J. Flores, J. Aceituno, P. J. Amado, A. Burdanov, Y. Calatayud-Borras, D. R. Ciardi, B. -O. Demory, T. Gan, S. Giacalone, M. Gillon, Y. Gómez Maqueo Chew , et al. (25 additional authors not shown)

Abstract: The Transiting Exoplanet Survey Satellite (TESS) has delivered a large number of transiting planet candidates around nearby stars by identifying periodic decreases in stellar brightness. Establishing the planetary nature of these signals and determining their fundamental properties is a necessary step toward detailed studies of their internal structure, atmospheres, and formation pathways. In this… ▽ More The Transiting Exoplanet Survey Satellite (TESS) has delivered a large number of transiting planet candidates around nearby stars by identifying periodic decreases in stellar brightness. Establishing the planetary nature of these signals and determining their fundamental properties is a necessary step toward detailed studies of their internal structure, atmospheres, and formation pathways. In this work, we investigate the planetary nature of the TOI-1752 system (M1 V, $103.02\pm0.34$ pc), which hosts two TESS candidates: TOI-1752 b, a short-period object consistent with a lava-world scenario, and TOI-1752 c, a sub-Neptune-size planet candidate located in the optimistic habitable zone. We obtained ground-based multi-color photometric follow-up observations of TOI-1752, which we combined with TESS photometry to assess the nature of both signals. We performed a formal statistical validation using the TRICERATOPS framework, while independently vetting the candidates with the neural-network-based classifier WATSON-Net, which provides a machine-learning assessment of their planetary likelihood based on light-curve morphology, centroid diagnostics, and auxiliary vetting features. We validate TOI-1752 b as a bona fide planet with a radius of $1.69\pm0.07 R_{\oplus}$ and an orbital period of $0.935186^{+0.000001}_{-0.000002}$ days, and TOI-1752 c with a radius of $2.29^{+0.13}_{-0.14} R_{\oplus}$ and an orbital period of $32.7144\pm0.0004$ days. The combined analysis confirms TOI-1752 as a new planetary system, places TOI-1752 c within the optimistic habitable zone of its host star, and identifies TOI-1752 b as a promising target for atmospheric characterization, with an estimated emission spectroscopy metric (ESM) of up to $\sim8$. △ Less

Submitted 17 April, 2026; originally announced April 2026.

Comments: 17 pages, 14 figures, 4 tables, accepted for publication in MNRAS

Raman and Terahertz Spectroscopy of Low-Frequency Chiral Phonons in Amino Acids

Authors: Rahul Rao, Won Jin Choi, Joseph M. Slocik, Thuc T. Mai, Michael A. Susner, Kelsey A. Collins, Michael J. Newburger, Petr Bouř, Nicholas A. Kotov

Abstract: Chiral phonons are mirror-symmetric vibrations that correspond to twisting and rotational motions of atoms. In chiral biomolecules, they correspond to low-energy terahertz (THz)-range vibrations of the molecular segments involving dozens of atoms whose energies are sensitive to the chirality of the molecules and local atomic geometries. Here we present spectral signatures of chiral phonons in circ… ▽ More Chiral phonons are mirror-symmetric vibrations that correspond to twisting and rotational motions of atoms. In chiral biomolecules, they correspond to low-energy terahertz (THz)-range vibrations of the molecular segments involving dozens of atoms whose energies are sensitive to the chirality of the molecules and local atomic geometries. Here we present spectral signatures of chiral phonons in circularly polarized low-frequency Raman and Raman optical activity (ROA) spectra from crystals of several amino acids in different enantiomeric forms. Along with complementary THz circular dichroism (TCD) measurements, our ROA data reveal two sets of bisignate peaks in valine, alanine, tyrosine and proline between 1 and 4.5 THz that are more intense than the ROA peaks in the fingerprint region. Density functional theory (DFT) calculations on L-alanine attribute these modes to twisting and shearing molecular motions. The strong agreement between the ROA and TCD data demonstrates the power of these complementary vibrational spectroscopy techniques to identify chiral phonons in biomolecules, and offers new insights into their vibrational properties and interactions with circularly polarized light. △ Less

Submitted 29 March, 2026; originally announced March 2026.

Comments: 14 pages, 3 figures

TOI-7169 b: A Hot Jupiter Transiting a Metal-Poor Star

Authors: Joshua D. Simon, Joseph E. Rodriguez, Jhon Yana Galarza, David W. Latham, Victoria DiTomasso, Karen A. Collins, Jack Schulte, Anirudh Chiti, Samuel N. Quinn, Mohammad K. Mardini, Shubham Kanodia, Johanna K. Teske, Peter S. Ferguson, Samuel W. Yee, T. G. Tan, Khalid Alsubai, Khalid Barkaoui, Zouhair Benkhaldoun, Krzysztof Bernacki, Jaikrit Bhattacharya, Jerome P. de Leon, Sarah J. Deveny, Mark E. Everett, Izuru Fukuda, Akihiko Fukui , et al. (16 additional authors not shown)

Abstract: Most known planets are found around metal-rich host stars, which has made it difficult to determine whether a lower metallicity limit for planet formation exists and how the properties of planets born in low-metallicity environments may differ from those with metal-rich origins. We present the discovery and characterization of TOI-7169 b (TIC 372048733 b), a hot Jupiter that is orbiting a spectros… ▽ More Most known planets are found around metal-rich host stars, which has made it difficult to determine whether a lower metallicity limit for planet formation exists and how the properties of planets born in low-metallicity environments may differ from those with metal-rich origins. We present the discovery and characterization of TOI-7169 b (TIC 372048733 b), a hot Jupiter that is orbiting a spectroscopically-confirmed metal-poor ([Fe/H] = -0.72 +/- 0.05) host star. Based on photometry from TESS and follow-up ground-based imaging, we measure an orbital period of 3.4373125 d and a planetary radius of 1.475 +/- 0.029 R_Jup. We use TRES spectroscopy to determine a mass for TOI-7169 b of 0.41 +/- 0.14 M_Jup. The planet is therefore inflated, with a low density of 0.159 +0.055/-0.054 g/cm^3. We also characterize the host star, showing that TOI-7169 is ancient (12.3 +/- 0.6 Gyr) and alpha-enhanced ([alpha/Fe] ~ 0.3), but with a Galactocentric orbit that is confined to the thin disk. TOI-7169 is perhaps the oldest and most metal-poor star currently known to host a transiting giant planet. Future transmission spectroscopy probing the atmosphere of TOI-7169 b may provide insight into the effect of metallicity on the physical properties of giant planets. △ Less

Submitted 23 June, 2026; v1 submitted 26 March, 2026; originally announced March 2026.

Comments: 21 pages, 9 figures, 6 tables. Accepted for publication in AJ

A Warm Massive Pair of Planets around TOI-1232 Revealed with Transit-timing Variations and Doppler Spectroscopy

Authors: Deyan P. Mihaylov, Jan Eberhardt, Trifon Trifonov, Rafael Brahm, Thomas Henning, Andrés Jordán, Denitza Stoeva, Matías I. Jones, Lorena Acuña-Aguirre, Stefan Stefanov, M. Tala Pinto, Melissa J. Hobson, Nestor Espinoza, Felipe I. Rojas, Martin Schlecker, Vladimir Bozhilov, Tristan Guillot, Amaury H. M. J. Triaud, Jack J. Lissauer, Judith Korth, Hannu Parviainen, Laura Kreidberg, Philippe Bendjoya, Olga Suarez, Carl Ziegler , et al. (10 additional authors not shown)

Abstract: TOI-1232 is a G-dwarf star with a mass of $1.06_{-0.06}^{+0.07} M_\odot$, a radius of $1.07\pm 0.05 R_\odot$, and slightly higher metallicity than solar of Fe/H = $0.18 \pm 0.05$. The star hosts a transiting warm Jovian-mass planet, TOI-1232 b, with an orbital period of $P_{b} = 14.256_{-0.001}^{+0.001}$ days, identified with data from multiple sectors of the $\textit{TESS}$ space telescope. The… ▽ More TOI-1232 is a G-dwarf star with a mass of $1.06_{-0.06}^{+0.07} M_\odot$, a radius of $1.07\pm 0.05 R_\odot$, and slightly higher metallicity than solar of Fe/H = $0.18 \pm 0.05$. The star hosts a transiting warm Jovian-mass planet, TOI-1232 b, with an orbital period of $P_{b} = 14.256_{-0.001}^{+0.001}$ days, identified with data from multiple sectors of the $\textit{TESS}$ space telescope. The $\textit{TESS}$ light curve of TOI-1232 is complex, as it is contaminated by a background eclipsing binary with a period of $1.37$ days. The TOI-1232 b was firmly confirmed by ground-based transit follow-up campaigns from Las Cumbres, Hazelwood, Brierfield, and ASTEP observatories.Additionally, the $\textit{TESS}$ transits of TOI-1232 b exhibit strong transit timing variations (TTVs) with a super-period of $235.5 \pm 0.7$ days and a semi-amplitude of 27 minutes. Radial velocity (RV) follow-up with the FEROS spectrograph confirms the planetary nature of the transiting candidate, while a self-consistent $N$-body analysis of RVs and TTVs pinpoints the presence of a second outer Saturn-mass companion, TOI-1232 c with a period of $P_{c} = 30.356_{-0.012}^{+0.010}$ days. The TOI-1232 warm-giant system is particularly important due to the evidence of two massive planets that reside near the 2:1 commensurability but are not locked in a mean motion resonance (MMR). Thanks to $\textit{TESS}$, we have revealed a handful of these rare systems. Hence, TOI-1232 is an important addition to understanding the formation and dynamical evolution of such compact, massive, warm giant planets. △ Less

Submitted 18 March, 2026; originally announced March 2026.

Comments: 33 pages, 17 figures, 8 tables

Journal ref: Deyan P. Mihaylov et al 2026 AJ 171 173

TOI-4552 b: A new ultra-short period rocky world revealed by NIRPS and TESS

Authors: Avidaan Srivastava, René Doyon, François Bouchy, Étienne Artigau, Charles Cadieux, Nicole Gromek, Elisa Delgado-Mena, Yuri S. Messias, Xavier Bonfils, Roseane de Lima Gomes, Susana C. C. Barros, Björn Benneke, Marta Bryan, Ryan Cloutier, Nicolas B. Cowan, Eduardo Cristo, Xavier Delfosse, Xavier Dumusque, David Ehrenreich, Jonay I. González Hernández, David Lafrenière, Izan de Castro Leão, Christophe Lovis, Alejandro Suárez Mascareño, Bruno L. Canto Martins , et al. (35 additional authors not shown)

Abstract: A particularly intriguing subclass of rocky exoplanets are the ultra-short period (USP) worlds that orbit their host stars in less than a day. These planets are particularly rare around M dwarf stars, with so far only ten that have a constrained mass and radius. We present the validation and characterization of the ultra-short period (0.3-days), Earth-sized planet TOI-4552b orbiting a nearby (27.2… ▽ More A particularly intriguing subclass of rocky exoplanets are the ultra-short period (USP) worlds that orbit their host stars in less than a day. These planets are particularly rare around M dwarf stars, with so far only ten that have a constrained mass and radius. We present the validation and characterization of the ultra-short period (0.3-days), Earth-sized planet TOI-4552b orbiting a nearby (27.26-pc away) M4.5V dwarf. Complementing the TESS photometry, ground-based transit observations from LCO, ExTrA and SPECULOOS validated the planetary radius and cleared the field of any contaminants. Speckle imaging with Zorro (Gemini-S) rules out false positive scenarios caused by eclipsing binary sources. Spectroscopic observations with NIRPS and HARPS were used to obtain stellar abundances, constrain the planetary mass, and, in conjunction with the transit observations, estimate the orbital parameters. TOI-4552 is a quiet star exhibiting no short-term stellar variations seen in photometric or radial velocity data that can be associated to stellar rotation. TOI-4552b ($M_p=1.83\pm0.47\,M_e$, $R_p=1.11\pm0.04\,R_e$) lies between the Earth-like and iron-rich composition tracks on the Mass-Radius diagram. The EXOPIE interior structure model, without constraints from refractory abundance ratio, yields a core mass fraction (CMF) of 0.54 and a bulk density of 7.74g/cm$^3$. Since the CMF spans a wide range due to the large uncertainty on the mass, the definitive interior composition cannot be determined with the current dataset. TOI-4552b hints as being marginally more iron-rich compared to the Earth but confirmation of its status requires additional, precise radial velocity measurements. Combined with its high emission spectroscopic metric (ESM=19.5), negligible stellar activity and short orbital period, TOI-4552b emerges as a compelling target for atmospheric and surface composition studies with JWST. △ Less

Submitted 18 March, 2026; originally announced March 2026.

Comments: 20 pages total: 12 pages main text + 8 pages appendix. Abstract shortened to fit character limit. Accepted to A&A on March 16, 2025

Journal ref: A&A 709, A73 (2026)

Confirmation of the hot super-Neptune TOI-672 b with NIRPS and HARPS and Insights into the Neptunian desert around M dwarfs

Authors: Ares Osborn, Ryan Cloutier, Vincent Bourrier, Bennett Skinner, Nicole Gromek, Avidaan Srivastava, François Bouchy, Marion Cointepas, Neil J. Cook, Nicola Nari, Jose Manuel Almenara, 'Etienne Artigau, Xavier Bonfils, Charles Cadieux, Patrick Eggenberger, Alexandrine L'Heureux, Frédérique Baron, Susana C. C. Barros, Björn Benneke, Marta Bryan, Bruno L. Canto Martins, Nicolas B. Cowan, Eduardo Cristo, Xavier Delfosse, Jose Renan De Medeiros , et al. (43 additional authors not shown)

Abstract: The Neptunian desert is a distinct lack of Neptune-sized planets at short orbital periods, purportedly carved by photoevaporation and tidal circularization following high-eccentricity migration. Constraining these processes and how they vary across different host-star spectral types requires the detailed characterization of planets in the desert and around its boundaries. In this study, we confirm… ▽ More The Neptunian desert is a distinct lack of Neptune-sized planets at short orbital periods, purportedly carved by photoevaporation and tidal circularization following high-eccentricity migration. Constraining these processes and how they vary across different host-star spectral types requires the detailed characterization of planets in the desert and around its boundaries. In this study, we confirm the planetary nature of a massive super-Neptune identified by TESS around the M0 dwarf TOI-672. We analyse photometry from TESS and ExTrA and precise radial velocity measurements taken with the recently commissioned Near-InfraRed Planet Searcher (NIRPS) and HARPS spectrographs. We measure the planetary orbital period, radius, and mass of 3.634 days, 5.31 +0.24 -0.26 Rearth, and 50.9 +4.5 -4.4 Mearth, respectively. Our findings place TOI-672 b within the Neptunian ridge, a pile-up of planets from 3--5 days at the Neptunian desert boundary. We then use a novel approach to determine the desert boundaries in period-radius space and instellation-radius space, and, for the first time, compare the Neptunian desert boundaries for planets orbiting FGK versus M dwarf stars. We determine that the boundary ridge shifts slightly inward from 3.3 +- 1.4 days for FGK host stars to 2.2 +- 1.0 days for M dwarf host stars; these values do not statistically significantly differ from each other, and the shift to shorter periods for M dwarf planets is smaller than theoretical photoevaporation models predict. We also find that TOI-672 b is a single-planet system within the sensitivity limits of our RV and TTV datasets. △ Less

Submitted 12 March, 2026; originally announced March 2026.

Comments: 23 pages + 8 pages appendices, 22 figures, 11 tables, data available in source files and at CDS/ExoFOP. Accepted for publication in A&A

Journal ref: A&A 709, A23 (2026)

Language Model Teams as Distributed Systems

Authors: Elizabeth Mieczkowski, Katherine M. Collins, Ilia Sucholutsky, Natalia Vélez, Thomas L. Griffiths

Abstract: Large language models (LLMs) are growing increasingly capable, prompting recent interest in LLM teams. Yet, despite increased deployment of LLM teams at scale, we lack a principled framework for addressing key questions such as when a team is helpful, how many agents to use, how structure impacts performance -- and whether a team is better than a single agent. Rather than designing and testing the… ▽ More Large language models (LLMs) are growing increasingly capable, prompting recent interest in LLM teams. Yet, despite increased deployment of LLM teams at scale, we lack a principled framework for addressing key questions such as when a team is helpful, how many agents to use, how structure impacts performance -- and whether a team is better than a single agent. Rather than designing and testing these possibilities through trial-and-error, we propose using distributed systems as a principled foundation for creating and evaluating LLM teams. We find that many of the fundamental advantages and challenges studied in distributed computing also arise in LLM teams, highlighting the rich practical insights that can come from the cross-talk of these two fields of study. △ Less

Submitted 12 March, 2026; originally announced March 2026.

TOI-4616 b: a benchmark Earth-sized planet transiting a nearby M4 dwarf

Authors: F. Zong Lang, B. O. Demory, Y. Gomez Maqueo Chew, Y. Schmid, M. Timmermans, F. J. Pozuelos, M. Gillon, Artem Y. Burdanov, Benjamin V. Rackham, Didier Queloz, Keivan G. Stassun, Khalid Barkaoui, Amaury Triaud, Julien de Wit, S. Zuniga-Fernandez, A. J. Burgasser, Elsa Ducrot, Madison G. Scott, D. Sebastian, A. Soubkiou, M. Lendl, I. Plauchu-Frayn, U. Schroffenegger, Erik Meier V., P. Pedersen , et al. (22 additional authors not shown)

Abstract: Rocky exoplanets are particularly abundant around M-type stars. Their small radii and low luminosities provide favourable conditions for detecting transiting terrestrial planets and probing their atmospheric properties. We report the discovery and statistical validation of TOI-4616 b, an Earth-sized planet transiting a nearby mid-M dwarf observed by the Transiting Exoplanet Survey Satellite (TES… ▽ More Rocky exoplanets are particularly abundant around M-type stars. Their small radii and low luminosities provide favourable conditions for detecting transiting terrestrial planets and probing their atmospheric properties. We report the discovery and statistical validation of TOI-4616 b, an Earth-sized planet transiting a nearby mid-M dwarf observed by the Transiting Exoplanet Survey Satellite (TESS). We confirm the planetary nature of the signal and determine the system parameters by combining TESS photometry with ground-based multi-band transit observations, high-resolution imaging, and optical and near-infrared spectroscopy. The host star lies at a distance of 28.10 +(-) 0.07 pc and has a radius of 0.1889 +(-)0.0096 solar radii, a mass of 0.1881 +(-) 0.0094 solar masses, and an effective temperature of 3150 +(-) 75 K. TOI-4616 b has a radius of 1.22 Earth radii and an orbital period of 1.55 days. The planet receives an incident flux of approximately 40 times that of Earth, corresponding to an equilibrium temperature of about 525 K. This places TOI-4616 b in a regime intermediate between Earth-sized planets orbiting early M dwarfs and those around ultra-cool hosts. Statistical validation with the TRICERATOPS framework, supported by high-resolution imaging and chromatic transit constraints, yields a false-positive probability of 0.0135, below the recommended validation threshold of 0.015, confirming TOI-4616 b as a validated planet. Owing to its proximity to Earth, well-constrained stellar properties, and extensive multi-band follow-up, TOI-4616 b constitutes a valuable benchmark system for comparative studies of terrestrial planets around mid-M dwarfs and for future atmospheric investigations. △ Less

Submitted 11 March, 2026; originally announced March 2026.

Comments: Submitted to MNRAS, 22 pages, 24 figures, 3 tables

Color $2$-switches and neighborhood $λ$-balanced graphs with $k$ colors

Authors: Karen L. Collins, Jonelle Hook, Cayla McBee, Ann N. Trenk

Abstract: This paper examines vertex colorings of graphs with constraints on the distribution of colors in vertex neighborhoods. We introduce color 2-switches and color degree matrices. The color degree matrix of a $k$-colored graph is an analog of the degree sequence, while a color 2-switch provides a way to transform a $k$-colored graph to another such graph while maintaining the color of each vertex and… ▽ More This paper examines vertex colorings of graphs with constraints on the distribution of colors in vertex neighborhoods. We introduce color 2-switches and color degree matrices. The color degree matrix of a $k$-colored graph is an analog of the degree sequence, while a color 2-switch provides a way to transform a $k$-colored graph to another such graph while maintaining the color of each vertex and the multiset of colors in each vertex neighborhood. We prove that two $k$-colored graphs have the same color degree matrix if and only if one can be obtained from the other by a sequence of color 2-switches. In related work, we generalize neighborhood balanced colorings by allowing for $k$ colors (instead of two) and more flexibility on the number of vertices of each color in a neighborhood. We introduce three classes of $k$-colored, $λ$-balanced graphs, in which any two color classes in a vertex neighborhood differ in size by at most $λ$. These classes are distinguished by whether the balancing condition is imposed on the open neighborhood $N(v)$, the closed neighborhood $N[v]$, or allowed to vary by vertex. For each class, the minimum $λ$ for which a graph admits a balanced coloring defines its $λ$-balance number. We prove general results about these classes and their $λ$-balance numbers. For $k = 2$, we introduce a fourth class, parity balanced graphs, in which the number of vertices of each color are equal in open neighborhoods for even-degree vertices and in closed neighborhoods for odd-degree vertices. Additionally, we focus on the important case where $k=2$ and $λ\le 1$ and introduce the technique of red-blue removals. We provide separating examples between these four classes and prove balance number results for paths, cycles, wheels, trees, caterpillars, and complete multipartite graphs, and a counting result for caterpillars. △ Less

Submitted 5 March, 2026; originally announced March 2026.

Comments: 24 pages, 10 figures

MSC Class: 05C15; 05C07

An Adolescent and Near-Resonant Planetary System Near the End of Photoevaporation

Authors: Mu-Tian Wang, Fei Dai, Hui-Gen Liu, Howard Chen, Zhecheng Hu, Erik Petigura, Steven Giacalone, Eve Lee, Max Goldberg, Adrien Leleu, Andrew W. Mann, Madyson G. Barber, Joshua N. Winn, Karen A. Collins, Cristilyn N. Watkins, Richard P. Schwarz, Howard M. Relles, Francis P. Wilkin, Enric Palle, Felipe Murgas, Avi Shporer, Ramotholo Sefako, Keith Horne, Hugh P. Osborn, Yann Alibert , et al. (6 additional authors not shown)

Abstract: Young exoplanets provide vital insights into the early dynamical and atmospheric evolution of planetary systems. Many multi-planet systems younger than 100 Myr exhibit mean-motion resonances, likely established through convergent disk migration. Over time, however, these resonant chains are often disrupted, mirroring the Nice model proposed for the Solar System. We present a detailed characterizat… ▽ More Young exoplanets provide vital insights into the early dynamical and atmospheric evolution of planetary systems. Many multi-planet systems younger than 100 Myr exhibit mean-motion resonances, likely established through convergent disk migration. Over time, however, these resonant chains are often disrupted, mirroring the Nice model proposed for the Solar System. We present a detailed characterization of the ~200-Myr-old TOI-2076 system, which contains four sub-Neptune planets between 1.4 and 3.5 Earth radii. We demonstrate that its planets are near but not locked in mean-motion resonances, making the system dynamically fragile. The four planets have comparable core masses but display a monotonic increase in hydrogen and helium (H/He) envelope mass fractions (stripped-1%-5%-5%) with decreasing stellar insolation. This trend is consistent with atmospheric mass-loss due to photoevaporation, which predicts that the envelopes of irradiated planets either erode completely or stabilize at a residual level of ~1% by mass within the first few hundred million years, with more distant, less-irradiated planets retaining most of primordial envelopes. Additionally, previous detections of metastable helium outflows rule out a pure water-world scenario for TOI-2076 planets. Our finding provides direct observational evidence that the dynamical and atmospheric reshaping of compact planetary systems begin early, offering an empirical anchor for models of their long-term evolution. △ Less

Submitted 2 March, 2026; originally announced March 2026.

Comments: Published on Nature Astronomy (https://www.nature.com/articles/s41550-026-02795-9)

TOI-1080 b: a temperate, rocky planet orbiting a quiet M4V host

Authors: Y. Gómez Maqueo Chew, G. Dransfield, K. Barkaoui, C. Cadieux, E. Ducrot, B. V. Rackham, M. Timmermans, A. J. Burgasser, A. Segura, K. G. Stassun, C. Ziegler, A. Soubkiou, J. M. Almenara, B. O. Demory, M. Gillon, J. M. Jenkins, E. Jofré, A. Khandelwal, S. Páez, R. Petrucci, L. Parc, M. Pichardo Marcano, I. Plauchu-Frayn, U. Schroffenegger, R. Schwarz , et al. (19 additional authors not shown)

Abstract: We present the detection and validation of a small, temperate transiting exoplanet orbiting TOI-1080 every 3.9652482$^{+0.0000014}_{-0.0000015}$ days. The host is a quiet M4V star at 25.6 pc. The planet signal was first detected by TESS and validated using TESS and ground-based observations. By fitting the available light curves, the planet radius is measured to be 1.200+- 0.058 Rearth and its equ… ▽ More We present the detection and validation of a small, temperate transiting exoplanet orbiting TOI-1080 every 3.9652482$^{+0.0000014}_{-0.0000015}$ days. The host is a quiet M4V star at 25.6 pc. The planet signal was first detected by TESS and validated using TESS and ground-based observations. By fitting the available light curves, the planet radius is measured to be 1.200+- 0.058 Rearth and its equilibrium temperature of 368$^{+12}_{-10}$ K. With NIRPS radial velocities, we are able to place a 3-sigma upper limit on the mass of TOI-1080 b of 10.7 Mearth. Our injection-recovery tests enable us to discard additional transiting planets in the TOI-1080 system with radii down to 0.9 Rearth and periods between 0.5 and 7.7 days, and planets with radii larger than 1.4 Rearth for periods up to 19 days. We demonstrate that it is highly amenable to characterisation of its mass and putative atmosphere. In particular, we find that TOI-1080 b is an exceptional target for the ongoing JWST+HST Rocky Worlds DDT programme, having a priority score that is higher than four out of nine targets currently being investigated by the programme. TOI-1080 b can be added to the sample of nearby benchmark planets accessible for detailed study with JWST. △ Less

Submitted 27 February, 2026; originally announced March 2026.

Comments: Joint first authorship between Y. Gómez Maqueo Chew and G. Dransfield, as these two authors contributed equally to this work. 15 pages, 14 figures. Accepted for publication in MNRAS

Under the Influence: Quantifying Persuasion and Vigilance in Large Language Models

Authors: Sasha Robinson, Katherine M. Collins, Ilia Sucholutsky, Kelsey R. Allen

Abstract: With increasing integration of Large Language Models (LLMs) into areas of high-stakes human decision-making, it is important to understand the risks they introduce as advisors. To be useful advisors, LLMs must sift through large amounts of content, written with both benevolent and malicious intent, and then use this information to convince a user to take a specific action. This involves two social… ▽ More With increasing integration of Large Language Models (LLMs) into areas of high-stakes human decision-making, it is important to understand the risks they introduce as advisors. To be useful advisors, LLMs must sift through large amounts of content, written with both benevolent and malicious intent, and then use this information to convince a user to take a specific action. This involves two social capacities: vigilance (the ability to determine which information to use, and which to discard) and persuasion (synthesizing the available evidence to make a convincing argument). While existing work has investigated these capacities in isolation, there has been little prior investigation of how these capacities may be linked. Here, we use a simple multi-turn puzzle-solving game, Sokoban, to study LLMs' abilities to persuade and be rationally vigilant towards other LLM agents. We find that puzzle-solving performance, persuasive capability, and vigilance are dissociable capacities in LLMs. Performing well on the game does not automatically mean a model can detect when it is being misled, even if the possibility of deception is explicitly mentioned. However, LLMs do consistently modulate their token use, using fewer tokens to reason when advice is benevolent and more when it is malicious, even if they are still persuaded to take actions leading them to failure. To our knowledge, our work presents the first investigation of the relationship between persuasion, vigilance, and task performance in LLMs, and suggests that monitoring all three independently will be critical for future work in AI safety. △ Less

Submitted 16 March, 2026; v1 submitted 23 February, 2026; originally announced February 2026.

PLATOSpec's first results: Three new transiting warm Jupiters from the WINE survey TIC 147027702, TIC 245076932 and TIC 87422071

Authors: Pavol Gajdoš, Rafael Brahm, Lorena Acuña-Aguirre, Matías I. Jones, Helem Salinas, Jozef Lipták, Andrés Jordán, Thomas Henning, Jiří Srba, Eva Žďárská, Zuzana Balkóová, Michaela Vítková, Jan Janík, Petr Škoda, Jiří Žák, Djamel Mekarnia, Olga Suarez, Lyu Abe, Matteo Beltrame, Amaury H. M. J. Triaud, Tristan Guillot, Karen A. Collins, Khalid Barkaoui, Gavin Boyle, Vincent Suc , et al. (11 additional authors not shown)

Abstract: We report the discovery and characterisation of three transiting warm Jupiters: TIC 147027702b, TIC 245076932b and TIC 87422071b. These systems were initially identified as transiting candidates using light curves generated from the full-frame images of the TESS mission. We confirmed the planetary nature of these objects with ground-based spectroscopic follow-up observations using FEROS and the ne… ▽ More We report the discovery and characterisation of three transiting warm Jupiters: TIC 147027702b, TIC 245076932b and TIC 87422071b. These systems were initially identified as transiting candidates using light curves generated from the full-frame images of the TESS mission. We confirmed the planetary nature of these objects with ground-based spectroscopic follow-up observations using FEROS and the new PLATOSpec spectrograph attached to the ESO 1.52 m telescope at the La Silla Observatory, and with ground-based photometric observations of the Observatoire Moana, Las Cumbres Observatory Global Telescope and ASTEP. From a global fit to the photometry and radial velocities, we determine that the planet TIC 147027702b has a low-eccentric orbit ($e = 0.13 \pm 0.05$) with a period of 44.4 days and has a mass of $1.09^{+0.07}_{-0.13}$ M$_J$ and a radius of $0.98 \pm 0.06$ R$_J$. TIC 245076932b has a moderately low mass of $0.51 \pm 0.05$ M$_J$, a radius of $0.97 \pm 0.05$ R$_J$, and an eccentric orbit ($e = 0.43 \pm 0.02$) with a period of 21.6 days. TIC 87422071b has a mass of $1.29 \pm 0.10$ M$_J$, a radius of $0.97 \pm 0.08$ R$_J$, and has a slightly eccentric orbit ($e = 0.12 \pm 0.07$) with a period of 11.3 days. These well-characterised warm Jupiters expand the currently limited sample of similar gas giants and provide valuable benchmarks for testing models of giant-planet formation, migration, and tidal evolution. △ Less

Submitted 24 February, 2026; originally announced February 2026.

Comments: revision version submitted to A&A

Journal ref: A&A 708, A189 (2026)

The Orbital Eccentricity--Radius Distribution for Warm, Single Planets in TESS

Authors: Tyler R. Fairnington, Jiayin Dong, Chelsea X. Huang, Emma Nabbie, George Zhou, Duncan Wright, Karen A. Collins, David Ciardi, Jon M. Jenkins, David W. Latham, George Ricker, Samuel N. Quinn, Sara Seager, Avi Shporer, Roland Vanderspek, Joshua N. Winn, Khalid Barkaoui, Allyson Bieryla, Lars Buchhave, Dmitry Cheryasov, Jessie Christiansen, Courtney Dressing, Akihiko Fukui, Alexey Garmash, Steven Giacalone , et al. (18 additional authors not shown)

Abstract: We characterize the radius-dependent eccentricity distribution of 219 warm (P = 8--50 days) systems with only one transiting planetary candidate identified during Sectors 1-69 of the TESS mission. Using the ``photoeccentric effect'' in a hierarchical Bayesian framework, we first model the population using discrete planetary size bins (sub-Neptunes, sub-Saturns, and Jovians). We then develop a cont… ▽ More We characterize the radius-dependent eccentricity distribution of 219 warm (P = 8--50 days) systems with only one transiting planetary candidate identified during Sectors 1-69 of the TESS mission. Using the ``photoeccentric effect'' in a hierarchical Bayesian framework, we first model the population using discrete planetary size bins (sub-Neptunes, sub-Saturns, and Jovians). We then develop a continuous mixture model with weights governed by a logistic sigmoid function of radius. We find that the warm-single population is best described by two components: a dominant low-eccentricity mode ( <e_low> = 0.039-0.038+0.018) and a secondary dynamically excited mode (<e_high> = 0.466-0.068+0.067). The fraction of planets belonging to this high-eccentricity component increases strongly with planet radius, characterized by a transition at a break radius of R_br = 9.2-1.1+1.9 R_e. This trend places warm sub-Saturns predominantly on the same low-eccentricity track as sub-Neptunes. In contrast, warm Jovians (8--16 R_e) are frequently eccentric, with 65-12+13% of the population in the high eccentricity mode. Under the assumption of a two-component model, we see tentative evidence for a bimodal Jovian distribution at ~2.7 sigma. Finally, we identify a non-negligible tail of highly eccentric sub-Neptunes (1--4 R_e), which comprise 16.2-6.4+5.2% of the population, consistent with excitation by non-transiting external companions. △ Less

Submitted 23 July, 2026; v1 submitted 23 February, 2026; originally announced February 2026.

Comments: Accepted for publication in ApJL

The GAPS Programme at the TNG: LXX. TOI-5734b: A hot sub-Neptune orbiting a relatively young K dwarf with an Earth-like density

Authors: S. Filomeno, T. Trifonov, M. Damasso, M. Baratella, S. Benatti, K. Biazzo, K. A. Collins, R. Cosentino, S. Desidera, C. Di Maio, D. Locci, A. Maggio, L. Mancini, S. Messina, L. Naponiello, D. Nardiello, K. G. Stassun, F. Amadori, S. Antoniucci, F. Biassoni, A. S. Bonomo, L. Cabona, C. A. Clark, M. Gonzalez, A. F. Lanza , et al. (18 additional authors not shown)

Abstract: Increasing interest in young exoplanets is leading to a growing effort to understand the formation and evolutionary processes responsible for their different architectures. One interesting target is TOI-5734, a relatively young K3-K4 dwarf star ($500_{-150}^{+300}$ Myr) showing a transiting candidate in photometric observations followed up with high-resolution spectroscopic data. Using Transiting… ▽ More Increasing interest in young exoplanets is leading to a growing effort to understand the formation and evolutionary processes responsible for their different architectures. One interesting target is TOI-5734, a relatively young K3-K4 dwarf star ($500_{-150}^{+300}$ Myr) showing a transiting candidate in photometric observations followed up with high-resolution spectroscopic data. Using Transiting Exoplanet Survey Satellite (TESS) photometry and High Accuracy Radial velocity Planet Searcher for the Northern hemisphere (HARPS-N) radial-velocity (RV) data, we aim to validate the presence of the companion TOI-5734b, measure its planetary mass, size, and its orbital parameters after having characterised its host star. We then aim to study its possible planetary composition and atmospheric evolution. By simultaneously modelling photometry and high-cadence RVs, we measured the radius, mass, and density of TOI-5734b precisely. In particular, we employed Gaussian processes (GPs) with a flexible kernel to discriminate between the stellar activity of the young host and planetary signals. We confirmed the planetary nature of TOI-5734b and measured its orbital period ($P_{\rm b}\sim6.18$ d), radius ($R_{\rm b} = 2.10^{+0.12}_{-0.12}$ $R_\oplus$), and mass ($M_{\rm b}=9.1^{+2.6}_{-2.6}$ $M_\oplus$). By measuring its density ($ρ_{\rm b}=0.98_{-0.30}^{+0.36}$ $ρ_\oplus$), we infer that TOI-5734b is close to having a rocky composition and an almost completely depleted primary envelope. Our results point toward the possibility of considering the target for atmospheric studies with present and future ground- and space-based facilities. △ Less

Submitted 20 February, 2026; originally announced February 2026.

Comments: 19 pages, 20 figures. Accepted for publication on A&A. Language editor corrected version. Abstract abridged

Journal ref: A&A 708, A90 (2026)

AI Gamestore: Scalable, Open-Ended Evaluation of Machine General Intelligence with Human Games

Authors: Lance Ying, Ryan Truong, Prafull Sharma, Kaiya Ivy Zhao, Nathan Cloos, Kelsey R. Allen, Thomas L. Griffiths, Katherine M. Collins, José Hernández-Orallo, Phillip Isola, Samuel J. Gershman, Joshua B. Tenenbaum

Abstract: Rigorously evaluating machine intelligence against the broad spectrum of human general intelligence has become increasingly important and challenging in this era of rapid technological advance. Conventional AI benchmarks typically assess only narrow capabilities in a limited range of human activity. Most are also static, quickly saturating as developers explicitly or implicitly optimize for them.… ▽ More Rigorously evaluating machine intelligence against the broad spectrum of human general intelligence has become increasingly important and challenging in this era of rapid technological advance. Conventional AI benchmarks typically assess only narrow capabilities in a limited range of human activity. Most are also static, quickly saturating as developers explicitly or implicitly optimize for them. We propose that a more promising way to evaluate human-like general intelligence in AI systems is through a particularly strong form of general game playing: studying how and how well they play and learn to play \textbf{all conceivable human games}, in comparison to human players with the same level of experience, time, or other resources. We define a "human game" to be a game designed by humans for humans, and argue for the evaluative suitability of this space of all such games people can imagine and enjoy -- the "Multiverse of Human Games". Taking a first step towards this vision, we introduce the AI GameStore, a scalable and open-ended platform that uses LLMs with humans-in-the-loop to synthesize new representative human games, by automatically sourcing and adapting standardized and containerized variants of game environments from popular human digital gaming platforms. As a proof of concept, we generated 100 such games based on the top charts of Apple App Store and Steam, and evaluated seven frontier vision-language models (VLMs) on short episodes of play. The best models achieved less than 10\% of the human average score on the majority of the games, and especially struggled with games that challenge world-model learning, memory and planning. We conclude with a set of next steps for building out the AI GameStore as a practical way to measure and drive progress toward human-like general intelligence in machines. △ Less

Submitted 19 February, 2026; originally announced February 2026.

Comments: 29 pages, 14 figures

Two warm sub-Saturn mass planets identified from the TESS Full Frame Images

Authors: Felipe I. Rojas, Rafael Brahm, Andrés Jordán, Néstor Espinoza, Thomas Henning, Jan Eberhardt, Melissa J. Hobson, Martin Schlecker, Marcelo Tala Pinto, Trifon Trifonov, Lyu Abe, Gaspar Bakos, Mauro Barbieri, Khalid Barkaoui, Christopher J. Burke, R. Paul Butler, Ilaria Carleo, Karen A. Collins, Jeffrey D. Crane, Zoltan Csubry, Phil Evans, Tristan Guillot, Chelsea X. Huang, Jon M. Jenkins, Matias I. Jones , et al. (25 additional authors not shown)

Abstract: Context. Characterization of warm giants is crucial to constrain giant planet formation and evolution. Measuring the mass and radius of these planets, combined with their moderated irradiation, allows us to estimate their planetary bulk composition, which is a key quantity to comprehend giant planet formation and structure. Aims. We present the discovery of two transiting warm giant planets orbiti… ▽ More Context. Characterization of warm giants is crucial to constrain giant planet formation and evolution. Measuring the mass and radius of these planets, combined with their moderated irradiation, allows us to estimate their planetary bulk composition, which is a key quantity to comprehend giant planet formation and structure. Aims. We present the discovery of two transiting warm giant planets orbiting solar-type stars from the Transiting Exoplanet Survey Satellite (TESS), which were characterized by further spectroscopic and photometric ground-based observations. Methods. We performed a joint analysis of photometric data with radial velocities to confirm and characterize TOI-883 b and TOI-899 b, two sub-Saturns orbiting solar-like stars. Results. TOI-883 b and TOI-899 b have masses of $0.123 \pm 0.012$ $M_J$ and $0.213 \pm 0.024$ $M_J$, radius of $0.604 \pm 0.028$ $R_J$ and $0.991 \pm 0.044$ $R_J$, periods of $10.06$ d and $12.85$ d and equilibrium temperature of $1086 \pm 19$ K and $1040 \pm 19$ K, respectively. Conclusions. While having similar masses, orbital periods and stellar host properties, these planets seem to have different internal compositions, which could point to distinct formation histories. Both planets are suitable targets for atmospheric studies to further constrain formation scenarios of planets in the Neptune-Saturn mass range △ Less

Submitted 18 February, 2026; originally announced February 2026.

Comments: 18 pages, 15 figures. Submitted to A&A

TIC-65910228 b / NGTS-38 b, a 180 day transiting warm super-Jupiter

Authors: Toby Rodel, Solène Ulmer-Moll, Samuel Gill, Christopher. A. Watson, Yoshi Nike Emilia Eschen, Alix V. Freckelton, Annelies Mortier, Karen A. Collins, Diana Dragomir, Zahra Essack, Brett Skinner, Niamh Mallaghan, Peter J. Wheatley, David R. Anderson, Ioannis Apergis, Khalid Barkaoui, Matthew P. Battley, Daniel Bayliss, François Bouchy, Edward M. Bryant, Matthew R. Burleigh, Benjamin M. J. Cadell, Samuel J. Carlier, Yann Carteret, Sarah L. Casewell , et al. (41 additional authors not shown)

Abstract: We present the discovery of TIC-65910228 b / NGTS-38 b, a giant exoplanet with a radius of $1.081\pm0.047$ R$_\text{J}$ and a mass of $4.78_{-0.37}^{+0.39}$ M$_\text{J}$ on a long-period ($180.52797\pm0.00036$ day), moderately eccentric ($e=0.3086\pm0.010$) orbit transiting a bright (V=$10.230\pm0.020$ mag) metal rich ([Fe/H]=$0.33\pm0.09$, 'dex') F6V-F7V type host star. The planet was initially d… ▽ More We present the discovery of TIC-65910228 b / NGTS-38 b, a giant exoplanet with a radius of $1.081\pm0.047$ R$_\text{J}$ and a mass of $4.78_{-0.37}^{+0.39}$ M$_\text{J}$ on a long-period ($180.52797\pm0.00036$ day), moderately eccentric ($e=0.3086\pm0.010$) orbit transiting a bright (V=$10.230\pm0.020$ mag) metal rich ([Fe/H]=$0.33\pm0.09$, 'dex') F6V-F7V type host star. The planet was initially detected from a single transit in TESS Sector 33. A photometric monitoring campaign of 228 nights with NGTS detected a transit egress of the planet, which together with spectroscopic radial velocity monitoring with CORALIE and HARPS identified an orbital period of ~180.5,d. These radial velocity measurements also showed the mass of the companion to be planetary. Additional transit observations coordinated by the TESS follow-up observing program allowed further confirmation and refinement of this period. With its relatively cool equilibrium temperature of $457\pm11$ K, NGTS-38 b joins a small but growing population of well characterised transiting warm-Jupiters and has one of the longest periods of any discovered to date. The target is situated in the LOPS2 field of the upcoming PLATO mission which will allow for greater refinement of the system parameters and potential for the discovery of additional companions too small and/or too long-period to be seen by TESS or NGTS. NGTS-38 b's bright host star and wide orbital separation make it an attractive target for further study, including potential measurement of its spin-orbit alignment or targeted exomoon/ring searches. △ Less

Submitted 4 June, 2026; v1 submitted 13 February, 2026; originally announced February 2026.

Comments: 26 pages, 13 figures, 8 tables. Accepted for Publication in Monthly Notices of the Royal Astronomical Society. Coordinated simultaneous submission with independent paper by Rojas et al

Journal ref: Mon Not R Astron Soc (2026)

Gas-depleted planet formation occurred in the four-planet system around the red dwarf LHS 1903

Authors: Thomas G. Wilson, Anna M. Simpson, Andrew Collier Cameron, Ryan Cloutier, Vardan Adibekyan, Ancy Anna John, Yann Alibert, Manu Stalport, Jo Ann Egger, Andrea Bonfanti, Nicolas Billot, Pascal Guterman, Pierre F. L. Maxted, Attila E. Simon, Sergio G. Sousa, Malcolm Fridlund, Mathias Beck, Anja Bekkelien, Sebastien Salmon, Valerie Van Grootel, Luca Fossati, Alexander James Mustill, Hugh P. Osborn, Tiziano Zingales, Matthew J. Hooton , et al. (151 additional authors not shown)

Abstract: Small exoplanet radii show two populations, referred to as super-Earths and sub-Neptunes, separated by a gap known as the radius valley. This may be produced by the removal of atmospheres due to stellar or internal heating, or lack of an initial envelope. We us transit photometry and radial velocity measurements to detect and characterize four planets orbiting LHS 1903, a red dwarf (M-dwarf) star… ▽ More Small exoplanet radii show two populations, referred to as super-Earths and sub-Neptunes, separated by a gap known as the radius valley. This may be produced by the removal of atmospheres due to stellar or internal heating, or lack of an initial envelope. We us transit photometry and radial velocity measurements to detect and characterize four planets orbiting LHS 1903, a red dwarf (M-dwarf) star in the Milky Way's thick disk. The planets have orbital periods between 2.2 and 29.3 days, and span the radius valley within a single planetary system. The derived densities indicate that LHS 1903 b is rocky, while LHS 1903 c and LHS 1903 d have extended atmospheres. Although the most distant planet from the host star, LHS 1903 e, has no gaseous envelope, indicating it formed from gas-depleted material. △ Less

Submitted 11 February, 2026; originally announced February 2026.

Comments: Accepted for publication in Science

Why Human Guidance Matters in Collaborative Vibe Coding

Authors: Haoyu Hu, Raja Marjieh, Katherine M Collins, Chenyi Li, Thomas L. Griffiths, Ilia Sucholutsky, Nori Jacoby

Abstract: Writing code has been one of the most transformative ways for human societies to translate abstract ideas into tangible technologies. Modern AI is changing this process by enabling experts and non-experts alike to generate code without actually writing it, instead using natural language instructions or "vibe coding". While increasingly popular, the impact of vibe coding on productivity and collabo… ▽ More Writing code has been one of the most transformative ways for human societies to translate abstract ideas into tangible technologies. Modern AI is changing this process by enabling experts and non-experts alike to generate code without actually writing it, instead using natural language instructions or "vibe coding". While increasingly popular, the impact of vibe coding on productivity and collaboration, and the role of humans in this process, remains unclear. Here, we introduce a controlled experimental framework for studying collaborative vibe coding and use it to compare human-led, AI-led, and hybrid groups. Across 20 experiments involving 737 human participants, we show that people provide uniquely effective high-level instructions for vibe coding, whereas AI-provided instructions often result in performance collapse. We further demonstrate that hybrid systems perform best when humans lead by providing instructions while evaluation is delegated to AI. Although AI systems can rapidly optimize performance for specific tasks, our work highlights the importance of human guidance in shaping future hybrid societies. △ Less

Submitted 5 March, 2026; v1 submitted 10 February, 2026; originally announced February 2026.

Human-AI Synergy Supports Collective Creative Search

Authors: Chenyi Li, Raja Marjieh, Haoyu Hu, Mark Steyvers, Katherine M. Collins, Ilia Sucholutsky, Nori Jacoby

Abstract: Generative AI is increasingly transforming creativity into a hybrid human-artificial process, but its impact on the quality and diversity of creative output remains unclear. We study collective creativity using a controlled word-guessing task that balances open-endedness with an objective measure of task performance. Participants attempt to infer a hidden target word, scored based on the semantic… ▽ More Generative AI is increasingly transforming creativity into a hybrid human-artificial process, but its impact on the quality and diversity of creative output remains unclear. We study collective creativity using a controlled word-guessing task that balances open-endedness with an objective measure of task performance. Participants attempt to infer a hidden target word, scored based on the semantic similarity of their guesses to the target, while also observing the best guess from previous players. We compare performance and outcome diversity across human-only, AI-only, and hybrid human-AI groups. Hybrid groups achieve the highest performance while preserving high diversity of guesses. Within hybrid groups, both humans and AI agents systematically adjust their strategies relative to single-agent conditions, suggesting higher-order interaction effects, whereby agents adapt to each other's presence. Although some performance benefits can be reproduced through collaboration between heterogeneous AI systems, human-AI collaboration remains superior, underscoring complementary roles in collective creativity. △ Less

Submitted 14 July, 2026; v1 submitted 10 February, 2026; originally announced February 2026.

Thermal Eclipse Observation of the Young Hot Neptune AU Mic b with Spitzer

Authors: Kevin I. Collins, Peter Plavchan, Zachory Berta-Thompson, Christoph Mordasini, Dan Huber, Jamie Tayar, Brice-Olivier Demory, Ward S. Howard, Nicholas Law, Thomas Barclay, Ian J. M. Crossfield, Diana Dragomir, Patrick J. Lowrance, Elisabeth R. Newton

Abstract: We present the observation of a secondary eclipse of the young hot Neptune, AU Mic b, in the infrared using the Spitzer Space Telescope. Using a primary transit from Spitzer to constrain the system parameters, we tentatively detect an eclipse centered at $BJD=2458740.848893^{+0.00010}_{-0.000099}$ with an observed depth of $171\pm{29}$ ppm given an uninformed prior. This corresponds to a dayside b… ▽ More We present the observation of a secondary eclipse of the young hot Neptune, AU Mic b, in the infrared using the Spitzer Space Telescope. Using a primary transit from Spitzer to constrain the system parameters, we tentatively detect an eclipse centered at $BJD=2458740.848893^{+0.00010}_{-0.000099}$ with an observed depth of $171\pm{29}$ ppm given an uninformed prior. This corresponds to a dayside brightness temperature of $T=1031\pm{58}$ K, which exceeds the calculated equilibrium temperature of $606\pm{19}$ K. We explore some possible explanations for these results, including inefficient heat redistribution, gravitational contraction, stellar pulsations, instrument systematics and choice of eclipse depth prior, but find none of these to be likely explanations for the observed eclipse parameters. We also explore the impact of correlated noise in the systematic trends, and we find that splitting the systematics into low-pass (smoothing) and high-pass trends is required to reach an optimal minimization of the low-frequency systematics in the resulting detrended light curve. Future observations with JWST are needed to confirm our eclipse detection with Spitzer. △ Less

Submitted 4 February, 2026; originally announced February 2026.

Comments: Submitted to AAS Journals, 29 pages, 34 figures, 6 tables

How do people watch AI-generated videos of physical scenes?

Authors: Danqing Shi, Lan Jiang, Katherine M. Collins, Shangzhe Wu, Ayush Tewari, Miri Zilka

Abstract: The growing prevalence of realistic AI-generated videos on media platforms increasingly blurs the line between fact and fiction, eroding public trust. Understanding how people watch AI-generated videos offers a human-centered perspective for improving AI detection and guiding advancements in video generation. However, existing studies have not investigated human gaze behavior in response to AI-gen… ▽ More The growing prevalence of realistic AI-generated videos on media platforms increasingly blurs the line between fact and fiction, eroding public trust. Understanding how people watch AI-generated videos offers a human-centered perspective for improving AI detection and guiding advancements in video generation. However, existing studies have not investigated human gaze behavior in response to AI-generated videos of physical scenes. Here, we collect and analyze the eye movements from 40 participants during video understanding and AI detection tasks involving a mix of real-world and AI-generated videos. We find that given the high realism of AI-generated videos, gaze behavior is driven less by the video's actual authenticity and more by the viewer's perception of its authenticity. Our results demonstrate that the mere awareness of potential AI generation may alter media consumption from passive viewing into an active search for anomalies. △ Less

Submitted 11 May, 2026; v1 submitted 3 February, 2026; originally announced February 2026.

Unraveling the Brown Dwarf Desert: Four New Discoveries and a Unifying, Period-Coded Picture

Authors: Ján Šubjak, Rafael Brahm, Jozef Lipták, Jan Eberhardt, Marcelo Tala Pinto, Sarah L. Casewell, Thomas Henning, Katharine Hesse, Trifon Trifonov, Andrés Jordán, Felipe I. Rojas, Michaela Vítková, Helem Salinas, Gavin Boyle, Vincent Suc, Luca Antonucci, Krzysztof Bernacki, César Briceño, Karen A. Collins, Jorge Fernández Fernández, Samuel Gill, Jan Janík, Nicholas Law, Andrew W. Mann, James McCormac , et al. (8 additional authors not shown)

Abstract: We present four newly validated transiting brown dwarfs identified through TESS photometry and confirmed with high-precision radial velocity measurements obtained from the FEROS and PLATOSpec spectrographs. Notably, three of these companions exhibit orbital periods exceeding 100 days, thereby expanding the sample of long-period transiting brown dwarfs from two to five systems. The host stars of lo… ▽ More We present four newly validated transiting brown dwarfs identified through TESS photometry and confirmed with high-precision radial velocity measurements obtained from the FEROS and PLATOSpec spectrographs. Notably, three of these companions exhibit orbital periods exceeding 100 days, thereby expanding the sample of long-period transiting brown dwarfs from two to five systems. The host stars of long-period brown dwarfs show mild subsolar metallicity. These discoveries highlight the expansion of the metal-poor, long-period distribution and help us better understand the brown dwarf desert. In our comparative analysis of eccentricity and metallicity demographics, we utilize catalogues of long-period giant planets, brown dwarfs, and low-mass stellar companions. After accounting for tidal influences, the eccentricity distribution aligns with that of low-mass stellar binaries, presenting a different profile than that observed within the giant planet population. Additionally, the metallicity of the host stars reveals a noteworthy trend: short-period transiting brown dwarfs are predominantly associated with metal-rich stars, whereas long-period brown dwarfs are more often found around metal-poor stars, demonstrating statistical similarities to low-mass stellar hosts. This trend has also been previously observed in studies of hot and cold Jupiters and points to a period-coded mixture of channels. A natural explanation is that most brown dwarfs originate from fragmentation at wider separations, with long-period systems retaining this stellar-like imprint, while only those embedded in massive, long-lived, metal-rich protoplanetary discs are efficiently delivered and stabilised to short orbits. △ Less

Submitted 2 February, 2026; originally announced February 2026.

Comments: 17 pages, 14 figures, submitted to Astronomy & Astrophysics

Journal ref: A&A 709, A130 (2026)