Showing 1–19 of 19 results for author: Tessenyi, M

The Preliminary Mauve Science Programme: Science themes identified for the first year of operations

Authors: Mauve Science Collaboration, Marcel Agueros, Don Dixon, Chuanfei Dong, Girish M. Duvvuri, Patrick Flanagan, Christopher Johns-Krull, Hongpeng Lu, Hiroyuki Maehara, Kosuke Namekata, Alejandro Nunez, Elena Pancino, Sharmila Rani, Anusha Ravikumar, T. A. A. Sigut, Keivan Stassun, Jamie Stewart, Krisztián Vida, Emma Whelan, Benjamin Wilcock, Sharafina Razin, Arianna Saba, Giovanna Tinetti, Marcell Tessenyi, Jonathan Tennyson

Abstract: Mauve is a low-cost small satellite developed and operated by Blue Skies Space Ltd. The payload features a 13 cm telescope connected with a fibre that feeds into a UV-Vis spectrometer. The detector covers the 200-700 nm range in a single shot, obtaining low resolution spectra at R~20-65. Mauve has launched on 28th November 2025, reaching a 510 km Low-Earth Sun-synchronous orbit. The satellite will… ▽ More Mauve is a low-cost small satellite developed and operated by Blue Skies Space Ltd. The payload features a 13 cm telescope connected with a fibre that feeds into a UV-Vis spectrometer. The detector covers the 200-700 nm range in a single shot, obtaining low resolution spectra at R~20-65. Mauve has launched on 28th November 2025, reaching a 510 km Low-Earth Sun-synchronous orbit. The satellite will enable UV and visible observations of a variety of stellar objects in our Galaxy, filling the gaps in the ultraviolet space-based data. The researchers that have already joined the mission have defined the science themes, observational strategy and targets that Mauve will observe in the first year of operations. To date 10 science themes have been developed by the Mauve science collaboration for year 1, with observational strategies that include both long duration monitoring and short cadence snapshots. Here, we describe these themes and the science that Mauve will undertake in its first year of operations. △ Less

Submitted 5 March, 2026; v1 submitted 18 December, 2025; originally announced December 2025.

Comments: 18 pages, 16 figures, 2 tables, accepted for publication on RASTI

Atmospheric Characterisation with the Twinkle Space Telescope Following Advances from JWST Observations

Authors: Tailong Zhang, Benjamin Wilcock, Sushuang Ma, Giovanna Tinetti, Lawrence Bradley, Ian Stotesbury, Marcell Tessenyi, Jonathan Tennyson

Abstract: The Twinkle Space Telescope is a satellite designed for spectroscopic observations of a wide range of extrasolar and solar system objects. Equipped with a 0.45 m diameter telescope and a spectrometer covering from 0.5 to 4.5 μm simultaneously, Twinkle will be launched in a sun-synchronous, low-Earth orbit, and it is expected to operate for seven years. Twinkle is developed, managed and operated by… ▽ More The Twinkle Space Telescope is a satellite designed for spectroscopic observations of a wide range of extrasolar and solar system objects. Equipped with a 0.45 m diameter telescope and a spectrometer covering from 0.5 to 4.5 μm simultaneously, Twinkle will be launched in a sun-synchronous, low-Earth orbit, and it is expected to operate for seven years. Twinkle is developed, managed and operated by Blue Skies Space (BSSL), a space science data company whose vision is to accelerate and expand the availability of new, high-quality datasets to researchers worldwide, complementing the space-observatories delivered by government space agencies. Over its life-time, Twinkle will conduct large-scale survey programs. The scientific objectives and observational strategy of these surveys are defined by researchers who join the Science Team. Leveraging advances made possible by recent observations with the James Webb Space Telescope, we present here updated simulations evaluating Twinkle's observational capabilities in the context of exoplanet atmospheres. Through retrieval analyses of HD 209458 b, WASP-107 b, GJ 3470 b, and 55 Cnc e, we demonstrate how increasing observational investment enhances the retrieval of atmospheric parameters and molecular abundances. Our sensitivity study highlights Twinkle's capability to detect less abundant/detectable molecules depending on the observing strategies adopted. This work provides practical guidance for developing targeted observational strategies to maximize Twinkle's scientific return. △ Less

Submitted 12 March, 2026; v1 submitted 14 August, 2025; originally announced August 2025.

MauveSim: the instrument simulator software for the Blue Skies Space Mauve satellite

Authors: Arianna Saba, Fabio Favata, Giorgio Savini, Giovanna Tinetti, Lawrence Bradley, Ian Stotesbury, Marcell Tessenyi

Abstract: We present MauveSim, the instrument simulator software for Mauve, the latest mission from Blue Skies Space dedicated to time-domain stellar astronomy. MauveSim functions as an end-to-end simulator, employing the most up-to-date knowledge of the instrument's performance and characteristics that will be reviewed and updated after commissioning. The software accepts a stellar spectrum - either observ… ▽ More We present MauveSim, the instrument simulator software for Mauve, the latest mission from Blue Skies Space dedicated to time-domain stellar astronomy. MauveSim functions as an end-to-end simulator, employing the most up-to-date knowledge of the instrument's performance and characteristics that will be reviewed and updated after commissioning. The software accepts a stellar spectrum - either observed or synthetic - as input and produces a simulated observation. The tool thus enables the assessment of various scientific objectives, as well as determining limiting magnitudes and conducting signal-to-noise (S/N) analyses. The results of MauveSim have been validated against instrument performance data from extensive ground testing campaigns, ensuring that the software reflects the most up-to-date understanding of the payload performance. Accessible to all scientists involved in the mission, MauveSim serves as a crucial tool for target selection and observation planning. △ Less

Submitted 23 September, 2025; v1 submitted 3 February, 2025; originally announced February 2025.

Comments: 13 pages, 3 tables, 15 figures, accepted for publication on RASTI

Twinkle -- a small satellite spectroscopy mission for the next phase of exoplanet science

Authors: Ian Stotesbury, Billy Edwards, Jean-Francois Lavigne, Vasco Pesquita, James J. Veilleux, Philip Windred, Ahmed Al-Refaie, Lawrence Bradley, Sushuang Ma, Giorgio Savini, Giovanna Tinetti, Til Birnstiel, Sally Dodson-Robinson, Barbara Ercolano, Dax Feliz, Scott Gaudi, Nina Hernitschek, Daniel Holdsworth, Ing-Guey Jiang, Matt Griffin, Nataliea Lowson, Karan Molaverdikhani, Hilding Neilson, Caprice Phillips, Thomas Preibisch , et al. (13 additional authors not shown)

Abstract: With a focus on off-the-shelf components, Twinkle is the first in a series of cost competitive small satellites managed and financed by Blue Skies Space Ltd. The satellite is based on a high-heritage Airbus platform that will carry a 0.45 m telescope and a spectrometer which will provide simultaneous wavelength coverage from 0.5-4.5 $\rm{μm}$. The spacecraft prime is Airbus Stevenage while the tel… ▽ More With a focus on off-the-shelf components, Twinkle is the first in a series of cost competitive small satellites managed and financed by Blue Skies Space Ltd. The satellite is based on a high-heritage Airbus platform that will carry a 0.45 m telescope and a spectrometer which will provide simultaneous wavelength coverage from 0.5-4.5 $\rm{μm}$. The spacecraft prime is Airbus Stevenage while the telescope is being developed by Airbus Toulouse and the spectrometer by ABB Canada. Scheduled to begin scientific operations in 2025, Twinkle will sit in a thermally-stable, sun-synchronous, low-Earth orbit. The mission has a designed operation lifetime of at least seven years and, during the first three years of operation, will conduct two large-scale survey programmes: one focused on Solar System objects and the other dedicated to extrasolar targets. Here we present an overview of the architecture of the mission, refinements in the design approach, and some of the key science themes of the extrasolar survey. △ Less

Submitted 7 September, 2022; originally announced September 2022.

Comments: Presented at SPIE Astronomical Telescopes & Instrumentation 2022

Journal ref: SPIE Proceedings Volume 12180, Space Telescopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave; 1218033 (2022)

Original Research By Young Twinkle Students (ORBYTS): Ephemeris Refinement of Transiting Exoplanets III

Authors: Billy Edwards, Cynthia S. K. Ho, Hannah L. M. Osborne, Nabeeha Deen, Ellie Hathorn, Solomon Johnson, Jiya Patel, Varun Vogireddy, Ansh Waddon, Ayuub Ahmed, Muhammad Bham, Nathan Campbell, Zahra Chummun, Nicholas Crossley, Reggie Dunsdon, Robert Hayes, Haroon Malik, Frank Marsden, Lois Mayfield, Liston Mitchell, Agnes Prosser, Valentina Rabrenovic, Emma Smith, Rico Thomas, Anastasia Kokori , et al. (4 additional authors not shown)

Abstract: We report photometric follow-up observations of thirteen exoplanets (HATS-1 b, HATS2 b, HATS-3 b, HAT-P-18 b, HAT-P-27 b, HAT-P-30 b, HAT-P-55 b, KELT-4A b, WASP-25 b, WASP-42 b, WASP-57 b, WASP-61 b and WASP-123 b), as part of the Original Research By Young Twinkle Students (ORBYTS) programme. All these planets are potentially viable targets for atmospheric characterisation and our data, which we… ▽ More We report photometric follow-up observations of thirteen exoplanets (HATS-1 b, HATS2 b, HATS-3 b, HAT-P-18 b, HAT-P-27 b, HAT-P-30 b, HAT-P-55 b, KELT-4A b, WASP-25 b, WASP-42 b, WASP-57 b, WASP-61 b and WASP-123 b), as part of the Original Research By Young Twinkle Students (ORBYTS) programme. All these planets are potentially viable targets for atmospheric characterisation and our data, which were taken using the LCOGT network of ground-based telescopes, will be combined with observations from other users of ExoClock to ensure that the transit times of these planets continue to be well-known, far into the future. △ Less

Submitted 20 July, 2022; v1 submitted 19 November, 2021; originally announced November 2021.

Comments: Accepted for publication in the Astronomy Theory, Observations and Methods Journal. Secondary school students (16-17 y/o) performed the majority of the analysis, as well as writing much of the paper, as part of the ORBYTS programme

Journal ref: Astronomy Theory, Observations and Methods Journal, Vol. 2, No. 1, August 2021

Original Research By Young Twinkle Students (ORBYTS): Ephemeris Refinement of Transiting Exoplanets

Authors: Billy Edwards, Quentin Changeat, Kai Hou Yip, Angelos Tsiaras, Jake Taylor, Bilal Akhtar, Josef AlDaghir, Pranup Bhattarai, Tushar Bhudia, Aashish Chapagai, Michael Huang, Danyaal Kabir, Vieran Khag, Summyyah Khaliq, Kush Khatri, Jaidev Kneth, Manisha Kothari, Ibrahim Najmudin, Lobanaa Panchalingam, Manthan Patel, Luxshan Premachandran, Adam Qayyum, Prasen Rana, Zain Shaikh, Sheryar Syed , et al. (38 additional authors not shown)

Abstract: We report follow-up observations of transiting exoplanets that have either large uncertainties (>10 minutes) in their transit times or have not been observed for over three years. A fully robotic ground-based telescope network, observations from citizen astronomers and data from TESS have been used to study eight planets, refining their ephemeris and orbital data. Such follow-up observations are k… ▽ More We report follow-up observations of transiting exoplanets that have either large uncertainties (>10 minutes) in their transit times or have not been observed for over three years. A fully robotic ground-based telescope network, observations from citizen astronomers and data from TESS have been used to study eight planets, refining their ephemeris and orbital data. Such follow-up observations are key for ensuring accurate transit times for upcoming ground and space-based telescopes which may seek to characterise the atmospheres of these planets. We find deviations from the expected transit time for all planets, with transits occurring outside the 1 sigma uncertainties for seven planets. Using the newly acquired observations, we subsequently refine their periods and reduce the current predicted ephemeris uncertainties to 0.28 - 4.01 minutes. A significant portion of this work has been completed by students at two high schools in London as part of the Original Research By Young Twinkle Students (ORBYTS) programme. △ Less

Submitted 4 May, 2020; originally announced May 2020.

Comments: Accepted for publication in MNRAS

Remote-sensing Characterisation of Major Solar System Bodies with the Twinkle Space Telescope

Authors: Billy Edwards, Giorgio Savini, Giovanna Tinetti, Marcell Tessenyi, Claudio Arena, Sean Lindsay, Neil Bowles

Abstract: Remote-sensing observations of Solar System objects with a space telescope offer a key method of understanding celestial bodies and contributing to planetary formation and evolution theories. The capabilities of Twinkle, a space telescope in a low Earth orbit with a 0.45m mirror, to acquire spectroscopic data of Solar System targets in the visible and infrared are assessed. Twinkle is a general ob… ▽ More Remote-sensing observations of Solar System objects with a space telescope offer a key method of understanding celestial bodies and contributing to planetary formation and evolution theories. The capabilities of Twinkle, a space telescope in a low Earth orbit with a 0.45m mirror, to acquire spectroscopic data of Solar System targets in the visible and infrared are assessed. Twinkle is a general observatory that provides on demand observations of a wide variety of targets within wavelength ranges that are currently not accessible using other space telescopes or that are accessible only to oversubscribed observatories in the short-term future. We determine the periods for which numerous Solar System objects could be observed and find that Solar System objects are regularly observable. The photon flux of major bodies is determined for comparison to the sensitivity and saturation limits of Twinkle's instrumentation and we find that the satellite's capability varies across the three spectral bands (0.4-1, 1.3-2.42, and 2.42-4.5μm). We find that for a number of targets, including the outer planets, their large moons, and bright asteroids, the model created predicts that with short exposure times, high-resolution spectra (R~250, λ < 2.42μm; R~60, λ > 2.42μm) could be obtained with signal-to-noise ratio (SNR) of >100 with exposure times of <300s. △ Less

Submitted 23 March, 2019; originally announced March 2019.

Journal ref: J. Astron. Telesc. Instrum. Syst. 5(1), 014006 (2019)

Small Bodies Science with Twinkle

Authors: Billy Edwards, Sean Lindsay, Giorgio Savini, Giovanna Tinetti, Claudio Arena, Neil Bowles, Marcell Tessenyi

Abstract: Twinkle is an upcoming 0.45m space-based telescope equipped with a visible and two near-infrared spectrometers covering the spectral range 0.4 to 4.5μm with a resolving power R~250 (λ<2.42μm) and R~60 (λ>2.42μm). We explore Twinkle's capabilities for small bodies science and find that, given Twinkle's sensitivity, pointing stability, and spectral range, the mission can observe a large number of sm… ▽ More Twinkle is an upcoming 0.45m space-based telescope equipped with a visible and two near-infrared spectrometers covering the spectral range 0.4 to 4.5μm with a resolving power R~250 (λ<2.42μm) and R~60 (λ>2.42μm). We explore Twinkle's capabilities for small bodies science and find that, given Twinkle's sensitivity, pointing stability, and spectral range, the mission can observe a large number of small bodies. The sensitivity of Twinkle is calculated and compared to the flux from an object of a given visible magnitude. The number, and brightness, of asteroids and comets that enter Twinkle's field of regard is studied over three time periods of up to a decade. We find that, over a decade, several thousand asteroids enter Twinkle's field of regard with a brightness and non-sidereal rate that will allow Twinkle to characterise them at the instrumentation's native resolution with SNR > 100. Hundreds of comets can also be observed. Therefore, Twinkle offers researchers the opportunity to contribute significantly to the field of Solar System small bodies research. △ Less

Submitted 19 September, 2019; v1 submitted 23 March, 2019; originally announced March 2019.

Comments: Published in JATIS

Journal ref: J. Astron. Telesc. Instrum. Syst. 5(3), 034004 (2019)

Exoplanet Spectroscopy and Photometry with the Twinkle Space Telescope

Authors: Billy Edwards, Malena Rice, Tiziano Zingales, Marcell Tessenyi, Ingo Waldmann, Giovanna Tinetti, Enzo Pascale, Giorgio Savini, Subhajit Sarkar

Abstract: The Twinkle space telescope has been designed for the characterisation of exoplanets and Solar System objects. Operating in a low Earth, Sun-synchronous orbit, Twinkle is equipped with a 45 cm telescope and visible (0.4 - 1um) and infrared (1.3 - 4.5um) spectrometers which can be operated simultaneously. Twinkle is a general observatory which will provide on-demand observations of a wide variety o… ▽ More The Twinkle space telescope has been designed for the characterisation of exoplanets and Solar System objects. Operating in a low Earth, Sun-synchronous orbit, Twinkle is equipped with a 45 cm telescope and visible (0.4 - 1um) and infrared (1.3 - 4.5um) spectrometers which can be operated simultaneously. Twinkle is a general observatory which will provide on-demand observations of a wide variety of targets within wavelength ranges that are currently not accessible using other space telescopes or accessible only to oversubscribed observatories in the short-term future. Here we explore the ability of Twinkle's spectrometers to characterise the currently-known exoplanets. We study the spectral resolution achievable by combining multiple observations for various planetary and stellar types. We also simulate spectral retrievals for some well-known planets (HD 209458 b, GJ 3470 b and 55 Cnc e). From the exoplanets known today, we find that with a single transit or eclipse, Twinkle could probe 89 planets at low spectral resolution (R < 20) as well as 12 planets at higher resolution (R > 20) in channel 1 (1.3 - 4.5um). With 10 observations, the atmospheres of 144 planets could be characterised with R < 20 and 81 at higher resolutions. Upcoming surveys will reveal thousands of new exoplanets, many of which will be located within Twinkle's field of regard. TESS in particular is predicted to discover many targets around bright stars which will be suitable for follow-up observations. We include these anticipated planets and find that the number of planets Twinkle could observe in the near infrared in a single transit or eclipse increases to 558 for R > 20 and 41 at lower resolutions. By stacking 10 transits or eclipses, there are 1185 potential targets for study at R < 20 as well as 388 planets at higher resolutions. △ Less

Submitted 22 December, 2018; v1 submitted 20 November, 2018; originally announced November 2018.

Journal ref: Experimental Astronomy, Issue Number 1572-9508, 08 December 2018

The EChO science case

Authors: Giovanna Tinetti, Pierre Drossart, Paul Eccleston, Paul Hartogh, Kate Isaak, Martin Linder, Christophe Lovis, Giusi Micela, Marc Ollivier, Ludovic Puig, Ignasi Ribas, Ignas Snellen, Bruce Swinyard. France Allard, Joanna Barstow, James Cho, Athena Coustenis, Charles Cockell, Alexandre Correia, Leen Decin, Remco de Kok, Pieter Deroo, Therese Encrenaz, Francois Forget, Alistair Glasse, Caitlin Griffith , et al. (326 additional authors not shown)

Abstract: The discovery of almost 2000 exoplanets has revealed an unexpectedly diverse planet population. Observations to date have shown that our Solar System is certainly not representative of the general population of planets in our Milky Way. The key science questions that urgently need addressing are therefore: What are exoplanets made of? Why are planets as they are? What causes the exceptional divers… ▽ More The discovery of almost 2000 exoplanets has revealed an unexpectedly diverse planet population. Observations to date have shown that our Solar System is certainly not representative of the general population of planets in our Milky Way. The key science questions that urgently need addressing are therefore: What are exoplanets made of? Why are planets as they are? What causes the exceptional diversity observed as compared to the Solar System? EChO (Exoplanet Characterisation Observatory) has been designed as a dedicated survey mission for transit and eclipse spectroscopy capable of observing a large and diverse planet sample within its four-year mission lifetime. EChO can target the atmospheres of super-Earths, Neptune-like, and Jupiter-like planets, in the very hot to temperate zones (planet temperatures of 300K-3000K) of F to M-type host stars. Over the next ten years, several new ground- and space-based transit surveys will come on-line (e.g. NGTS, CHEOPS, TESS, PLATO), which will specifically focus on finding bright, nearby systems. The current rapid rate of discovery would allow the target list to be further optimised in the years prior to EChO's launch and enable the atmospheric characterisation of hundreds of planets. Placing the satellite at L2 provides a cold and stable thermal environment, as well as a large field of regard to allow efficient time-critical observation of targets randomly distributed over the sky. A 1m class telescope is sufficiently large to achieve the necessary spectro-photometric precision. The spectral coverage (0.5-11 micron, goal 16 micron) and SNR to be achieved by EChO, thanks to its high stability and dedicated design, would enable a very accurate measurement of the atmospheric composition and structure of hundreds of exoplanets. △ Less

Submitted 19 February, 2015; originally announced February 2015.

Comments: 50 pages, 30 figures. Experimental Astronomy

Influence of different parameters on the chemical composition of warm neptunes

Authors: Olivia Venot, Marcelino Agúndez, Franck Selsis, Marcell Tessenyi, Leen Decin

Abstract: We developed a 1D photo-thermochemical model to study the atmosphere of warm exoplanets. The chemical scheme used in this model is completely new in planetology and has been constructed in collaboration with specialists of combustion. It has been validated as a whole through experiments on a large range of temperature (300 - 2500 K) and pressure (1 mbar - 100 bar), allowing to study a wide variety… ▽ More We developed a 1D photo-thermochemical model to study the atmosphere of warm exoplanets. The chemical scheme used in this model is completely new in planetology and has been constructed in collaboration with specialists of combustion. It has been validated as a whole through experiments on a large range of temperature (300 - 2500 K) and pressure (1 mbar - 100 bar), allowing to study a wide variety of exoplanets. We have used this chemical model to study the atmosphere of two warm Neptunes, GJ3470b and GJ436b, and the influence of different parameters (vertical mixing, metallicity, temperature, . . . ) on their chemical composition. We present here the results obtained in these studies. △ Less

Submitted 4 December, 2014; v1 submitted 2 December, 2014; originally announced December 2014.

Comments: 5 pages, 2 figure, 1 table, SF2A Proceedings, accepted

EChOSim: The Exoplanet Characterisation Observatory software simulator

Authors: E. Pascale, I. P. Waldmann, C. J. MacTavish, A. Papageorgiou, A. Amaral-Rogers, R. Varley, V. Coudé de Foresto, M. J. Griffin, M. Ollivier, S. Sarkar, L. Spencer, B. M. Swinyard, M. Tessenyi, G. Tinetti

Abstract: EChOSim is the end-to-end time-domain simulator of the Exoplanet Characterisation Observatory (EChO) space mission. EChOSim has been developed to assess the capability EChO has to detect and characterize the atmospheres of transiting exoplanets, and through this revolutionize the knowledge we have of the Milky Way and of our place in the Galaxy. Here we discuss the details of the EChOSim implement… ▽ More EChOSim is the end-to-end time-domain simulator of the Exoplanet Characterisation Observatory (EChO) space mission. EChOSim has been developed to assess the capability EChO has to detect and characterize the atmospheres of transiting exoplanets, and through this revolutionize the knowledge we have of the Milky Way and of our place in the Galaxy. Here we discuss the details of the EChOSim implementation and describe the models used to represent the instrument and to simulate the detection. Software simulators have assumed a central role in the design of new instrumentation and in assessing the level of systematics affecting the measurements of existing experiments. Thanks to its high modularity, EChOSim can simulate basic aspects of several existing and proposed spectrometers for exoplanet transits, including instruments on the Hubble Space Telescope and Spitzer, or ground-based and balloon borne experiments. A discussion of different uses of EChOSim is given, including examples of simulations performed to assess the EChO mission. △ Less

Submitted 16 June, 2014; originally announced June 2014.

Generation of an optimal target list for the Exoplanet Characterisation Observatory (EChO)

Authors: Ryan Varley, Ingo Waldmann, Enzo Pascale, Marcell Tessenyi, Morgan Hollis, Juan Carlos Morales, Giovanna Tinetti, Bruce Swinyard, Pieter Deroo, Marc Ollivier, Giusi Micela

Abstract: The Exoplanet Characterisation Observatory (EChO) has been studied as a space mission concept by the European Space Agency in the context of the M3 selection process. Through direct measurement of the atmospheric chemical composition of hundreds of exoplanets, EChO would address fundamental questions such as: What are exoplanets made of? How do planets form and evolve? What is the origin of exopla… ▽ More The Exoplanet Characterisation Observatory (EChO) has been studied as a space mission concept by the European Space Agency in the context of the M3 selection process. Through direct measurement of the atmospheric chemical composition of hundreds of exoplanets, EChO would address fundamental questions such as: What are exoplanets made of? How do planets form and evolve? What is the origin of exoplanet diversity? More specifically, EChO is a dedicated survey mission for transit and eclipse spectroscopy capable of observing a large, diverse and well-defined planetary sample within its four to six year mission lifetime. In this paper we use the end-to-end instrument simulator EChOSim to model the currently discovered targets, to gauge which targets are observable and assess the EChO performances obtainable for each observing tier and time. We show that EChO would be capable of observing over 170 relativity diverse planets if it were launched today, and the wealth of optimal targets for EChO expected to be discovered in the next 10 years by space and ground-based facilities is simply overwhelming. In addition, we build on previous molecular detectability studies to show what molecules and abundances will be detectable by EChO for a selection of real targets with various molecular compositions and abundances. EChO's unique contribution to exoplanetary science will be in identifying the main constituents of hundreds of exoplanets in various mass/temperature regimes, meaning that we will be looking no longer at individual cases but at populations. Such a universal view is critical if we truly want to understand the processes of planet formation and evolution in various environments. In this paper we present a selection of key results. The full results are available online (http://www.ucl.ac.uk/exoplanets/echotargetlist/). △ Less

Submitted 5 January, 2015; v1 submitted 3 March, 2014; originally announced March 2014.

Comments: Accepted for publication in Experimental Astronomy, 20 pages, 10 figures, 3 tables

The atmospheric chemistry of the warm Neptune GJ 3470b: influence of metallicity and temperature on the CH4/CO ratio

Authors: Olivia Venot, Marcelino Agundez, Franck Selsis, Marcell Tessenyi, Nicolas Iro

Abstract: Current observation techniques are able to probe the atmosphere of some giant exoplanets and get some clues about their atmospheric composition. However, the chemical compositions derived from observations are not fully understood, as for instance in the case of the CH4/CO abundance ratio, which is often inferred different from what has been predicted by chemical models. Recently, the warm Neptune… ▽ More Current observation techniques are able to probe the atmosphere of some giant exoplanets and get some clues about their atmospheric composition. However, the chemical compositions derived from observations are not fully understood, as for instance in the case of the CH4/CO abundance ratio, which is often inferred different from what has been predicted by chemical models. Recently, the warm Neptune GJ3470b has been discovered and because of its close distance from us and high transit depth, it is a very promising candidate for follow up characterisation of its atmosphere. We study the atmospheric composition of GJ3470b in order to compare with the current observations of this planet, to prepare the future ones, but also as a typical case study to understand the chemical composition of warm (sub-)Neptunes. The metallicity of such atmospheres is totally uncertain, and vary probably to values up to 100x solar. We explore the space of unknown parameters to predict the range of possible atmospheric compositions. Within the parameter space explored we find that in most cases methane is the major carbon-bearing species. We however find that in some cases, typically for high metallicities with a sufficiently high temperature the CH4/CO abundance ratio can become lower than unity, as suggested by some multiwavelength photometric observations of other warm (sub-)Neptunes, such as GJ1214b and GJ436b. As for the emission spectrum of GJ3470b, brightness temperatures at infrared wavelengths may vary between 400 and 800K depending on the thermal profile and metallicity. Combined with a hot temperature profile, a substantial enrichment in heavy elements by a factor of 100 with respect to the solar composition can shift the carbon balance in favour of carbon monoxide at the expense of CH4. Nevertheless, current observations of this planet do not allow yet to determine which model is more accurate. △ Less

Submitted 18 December, 2013; originally announced December 2013.

Comments: 12 pages, 8 figures, accepted in Astronomy & Astrophysics

TAU: A 1D radiative transfer code for transmission spectroscopy of extrasolar planet atmospheres

Authors: M. D. J. Hollis, M. Tessenyi, G. Tinetti

Abstract: The TAU code is a 1D line-by-line radiative transfer code, which is generally applicable for modelling transmission spectra of close-in extrasolar planets. The inputs are the assumed pressure-temperature profile of the planetary atmosphere, the continuum absorption coefficients and the absorption cross-sections for the trace molecular absorbers present in the model, as well as the fundamental syst… ▽ More The TAU code is a 1D line-by-line radiative transfer code, which is generally applicable for modelling transmission spectra of close-in extrasolar planets. The inputs are the assumed pressure-temperature profile of the planetary atmosphere, the continuum absorption coefficients and the absorption cross-sections for the trace molecular absorbers present in the model, as well as the fundamental system parameters taken from the published literature. The program then calculates the optical path through the planetary atmosphere of the radiation from the host star, and quantifies the absorption due to the modelled composition in a transmission spectrum of transit depth as a function of wavelength. The code is written in C++, parallelised using OpenMP, and is available for public download and use from http://www.ucl.ac.uk/exoplanets/. △ Less

Submitted 6 September, 2013; v1 submitted 13 May, 2013; originally announced May 2013.

Comments: 29 pages, 7 figures

Journal ref: Computer Physics Communications 184, pp.2351-2361 (2013)

Photometric stability analysis of the Exoplanet Characterisation Observatory

Authors: I. P. Waldmann, E. Pascale, B. Swinyard, G. Tinetti, A. Amaral-Rogers, L. Spencer, M. Tessenyi, M. Ollivier, V. Coudé du Foresto

Abstract: Photometric stability is a key requirement for time-resolved spectroscopic observations of transiting extrasolar planets. In the context of the Exoplanet Characterisation Observatory (EChO) mission design, we here present and investigate means of translating spacecraft pointing instabilities as well as temperature fluctuation of its optical chain into an overall error budget of the exoplanetary sp… ▽ More Photometric stability is a key requirement for time-resolved spectroscopic observations of transiting extrasolar planets. In the context of the Exoplanet Characterisation Observatory (EChO) mission design, we here present and investigate means of translating spacecraft pointing instabilities as well as temperature fluctuation of its optical chain into an overall error budget of the exoplanetary spectrum to be retrieved. Given the instrument specifications as of date, we investigate the magnitudes of these photometric instabilities in the context of simulated observations of the exoplanet HD189733b secondary eclipse. △ Less

Submitted 26 February, 2013; originally announced February 2013.

Comments: submitted to MNRAS

Probing the extreme planetary atmosphere of WASP-12b

Authors: Mark Swain, Pieter Deroo, Giovanna Tinetti, Morgan Hollis, Marcell Tessenyi, Michael Line, Hajime Kawahara, Yuka Fujii, Adam Showman, Sergey Yurchenko

Abstract: We report near-infrared measurements of the terminator region transmission spectrum and dayside emission spectrum of the exoplanet WASP-12b obtained using the HST WFC3 instrument. The disk-average dayside brightness temperature averages about 2900 K, peaking to 3200 K around 1.46 microns. We modeled a range of atmospheric cases for both the emission and transmission spectrum and confirm the recent… ▽ More We report near-infrared measurements of the terminator region transmission spectrum and dayside emission spectrum of the exoplanet WASP-12b obtained using the HST WFC3 instrument. The disk-average dayside brightness temperature averages about 2900 K, peaking to 3200 K around 1.46 microns. We modeled a range of atmospheric cases for both the emission and transmission spectrum and confirm the recent finding by Crossfield et al. (2012b) that there is no evidence for C/O >1 in the atmosphere of WASP-12b. Assuming a physically plausible atmosphere, we find evidence that the presence of a number of molecules is consistent with the data, but the justification for inclusion of these opacity sources based on the Bayesian Information Criterion (BIC) is marginal. We also find the near-infrared primary eclipse light curve is consistent with small amounts of prolate distortion. As part of the calibration effort for these data, we conducted a detailed study of instrument systematics using 65 orbits of WFC3-IR grims observations. The instrument systematics are dominated by detector-related affects, which vary significantly depending on the detector readout mode. The 256x256 subarray observations of WASP 12 produced spectral measurements within 15% of the photon-noise limit using a simple calibration approach. Residual systematics are estimated to be less than 70 parts per million. △ Less

Submitted 22 May, 2013; v1 submitted 21 May, 2012; originally announced May 2012.

Comments: Accepted for publication in Icarus

EChO - Exoplanet Characterisation Observatory

Authors: G. Tinetti, J. P. Beaulieu, T. Henning, M. Meyer, G. Micela, I. Ribas, D. Stam, M. Swain, O. Krause, M. Ollivier, E. Pace, B. Swinyard, A. Aylward, R. van Boekel, A. Coradini, T. Encrenaz, I. Snellen, M. R. Zapatero-Osorio, J. Bouwman, J. Y-K. Cho, V. Coudé du Foresto, T. Guillot, M. Lopez-Morales, I. Mueller-Wodarg, E. Palle , et al. (109 additional authors not shown)

Abstract: A dedicated mission to investigate exoplanetary atmospheres represents a major milestone in our quest to understand our place in the universe by placing our Solar System in context and by addressing the suitability of planets for the presence of life. EChO -the Exoplanet Characterisation Observatory- is a mission concept specifically geared for this purpose. EChO will provide simultaneous, multi-w… ▽ More A dedicated mission to investigate exoplanetary atmospheres represents a major milestone in our quest to understand our place in the universe by placing our Solar System in context and by addressing the suitability of planets for the presence of life. EChO -the Exoplanet Characterisation Observatory- is a mission concept specifically geared for this purpose. EChO will provide simultaneous, multi-wavelength spectroscopic observations on a stable platform that will allow very long exposures. EChO will build on observations by Hubble, Spitzer and groundbased telescopes, which discovered the first molecules and atoms in exoplanetary atmospheres. EChO will simultaneously observe a broad enough spectral region -from the visible to the mid-IR- to constrain from one single spectrum the temperature structure of the atmosphere and the abundances of the major molecular species. The spectral range and resolution are tailored to separate bands belonging to up to 30 molecules to retrieve the composition and temperature structure of planetary atmospheres. The target list for EChO includes planets ranging from Jupiter-sized with equilibrium temperatures Teq up to 2000 K, to those of a few Earth masses, with Teq ~300 K. We have baselined a dispersive spectrograph design covering continuously the 0.4-16 micron spectral range in 6 channels (1 in the VIS, 5 in the IR), which allows the spectral resolution to be adapted from several tens to several hundreds, depending on the target brightness. The instrument will be mounted behind a 1.5 m class telescope, passively cooled to 50 K, with the instrument structure and optics passively cooled to ~45 K. EChO will be placed in a grand halo orbit around L2. We have also undertaken a first-order cost and development plan analysis and find that EChO is easily compatible with the ESA M-class mission framework. △ Less

Submitted 12 December, 2011; originally announced December 2011.

Comments: Accepted for publication in Experimental Astronomy, 23 pages, 15 figures

Characterising the Atmospheres of Transiting Planets with a Dedicated Space Telescope

Authors: M. Tessenyi, M. Ollivier, G. Tinetti, J. P. Beaulieu, V. Coudé du Foresto, T. Encrenaz, G. Micela, B. Swinyard, I. Ribas, A. Aylward, J. Tennyson, M. R. Swain, A. Sozzetti, G. Vasisht, P. Deroo

Abstract: Exoplanetary science is among the fastest evolving fields of today's astronomical research. Ground-based planet-hunting surveys alongside dedicated space missions (Kepler, CoRoT) are delivering an ever-increasing number of exoplanets, now numbering at ~690, with ESA's GAIA mission planned to bring this number into the thousands. The next logical step is the characterisation of these worlds: what i… ▽ More Exoplanetary science is among the fastest evolving fields of today's astronomical research. Ground-based planet-hunting surveys alongside dedicated space missions (Kepler, CoRoT) are delivering an ever-increasing number of exoplanets, now numbering at ~690, with ESA's GAIA mission planned to bring this number into the thousands. The next logical step is the characterisation of these worlds: what is their nature? Why are they as they are? The use of the HST and Spitzer Space Telescope to probe the atmospheres of transiting hot, gaseous exoplanets has demonstrated that it is possible with current technology to address this ambitious goal. The measurements have also shown the difficulty of understanding the physics and chemistry of these environments when having to rely on a limited number of observations performed on a handful of objects. To progress substantially in this field, a dedicated facility for exoplanet characterization with an optimised instrument design (detector performance, photometric stability, etc.), able to observe through time and over a broad spectral range a statistically significant number of planets, will be essential. We analyse the performances of a 1.2/1.4m space telescope for exoplanet transit spectroscopy from the visible to the mid IR, and present the SNR ratio as function of integration time and stellar magnitude/spectral type for the acquisition of spectra of planetary atmospheres in a variety of scenarios: hot, warm, and temperate planets, orbiting stars ranging in spectral type from hot F to cool M dwarfs. We include key examples of known planets (e.g. HD 189733b, Cancri 55 e) and simulations of plausible terrestrial and gaseous planets, with a variety of thermodynamical conditions. We conclude that even most challenging targets, such as super-Earths in the habitable-zone of late-type stars, are within reach of a M-class, space-based spectroscopy mission. △ Less

Submitted 24 November, 2011; v1 submitted 6 November, 2011; originally announced November 2011.

Comments: v2: minor corrections