Showing 1–16 of 16 results for author: Jagadeesh, K

Habitability Study of Terrestrial Planets: Application to Venus-like Worlds

Authors: Swathi Raviprakash, Madhu Kashyap Jagadeesh, Margarita Safonova, Oleg Kotsyurbenko

Abstract: The study of planetary habitability beyond Earth remains central and a challenging project in planetary science. Analysis of large volumes of planetary data from space missions such as CoRoT, Kepler, and JWST is directed ultimately at finding a planet similar to Earth, the Earth's twin, and answering the question of potential exo-habitability. The Earth Similarity Index (ESI) is a first step in th… ▽ More The study of planetary habitability beyond Earth remains central and a challenging project in planetary science. Analysis of large volumes of planetary data from space missions such as CoRoT, Kepler, and JWST is directed ultimately at finding a planet similar to Earth, the Earth's twin, and answering the question of potential exo-habitability. The Earth Similarity Index (ESI) is a first step in this quest, ranging from 1 (Earth) to 0 (totally dissimilar to Earth). To identify planets that may be habitable to the extreme forms of life, we introduce the Mars Similarity Index (MSI). However, extreme forms of life have also been hypothesized under specific conditions in the upper atmosphere of Venus, motivating comparative habitability studies beyond Earth and Mars. The Venus Similarity Index (VSI), introduced here, is defined as the geometric mean of radius, density, escape velocity, and surface temperature, normalized in Venus units (VU). VSI values range from 0 (complete dissimilarity) to 1 (maximum similarity). The VSI provides a comparative framework for identifying Venus-like planetary environments within exoplanet populations. To explore habitability evolution, we further introduce the Ancient Venus Similarity Index (AVSI) and the Future Earth Similarity Index (FESI) to examine early Venusian conditions relative to ancient Earth and to assess potential future evolutionary pathways for Earth-like planets. △ Less

Submitted 11 August, 2026; v1 submitted 8 April, 2026; originally announced April 2026.

Comments: 21 pages, 10 figures, 5 tables. Accepted for publication in the Journal of Astrophysics and Astronomy (JAA)

Classification and Nomenclature of Planets in the Mass-Radius Plane

Authors: Madhu Kashyap Jagadeesh, Arkil Parikh, Margarita Safonova, Bernard Foing, Oleg Kotsyurbenko

Abstract: 6500+ exoplanets have been detected using various techniques. This prompted the emergence of many recent works on the taxonomy, or classification, of exoplanets. However, there is still no basic, fundamental definition of 'What is a planet?'. IAU has forwarded a definition in 2006, which however, raised more questions than it solved. The first task here is to establish if there are limits on the s… ▽ More 6500+ exoplanets have been detected using various techniques. This prompted the emergence of many recent works on the taxonomy, or classification, of exoplanets. However, there is still no basic, fundamental definition of 'What is a planet?'. IAU has forwarded a definition in 2006, which however, raised more questions than it solved. The first task here is to establish if there are limits on the size/mass of planets. The lower mass limit may be assumed as of Mimas (0.03 EU) - approximately minimum mass required to attain a nearly spherical hydrostatic equilibrium shape. The upper mass limit may be easier - there is a natural lower limit to what constitutes a star: 0.08 SU. But then there are brown dwarfs: IAU has defined brown dwarfs as objects exceeding the deuterium burning limit (~13 JU), and giant exoplanets generally have masses of 0.3 to 60 JU. The resolution requires assembling the basic physical parameters that define planets quantitatively. Mass and radius are the two fundamental properties, and we propose to use a third correlated parameter: the moment of inertia. Based on this, we create the parametric Fundamental Planetary Plane where the two parameters are correlated with the third. The fundamental planetary plane (FPP) with turn-off point diagrams is constructed for visual representation. We propose an alternate potential description of a planet definition as 'A celestial spherical object, bound to a star or unbound, that lies on the fundamental planetary plane, within a mass range between 0.02 EU to 13 JU'. This definition is intended to complement existing taxonomies by providing a quantitative, structure-based criterion applicable to both Solar System planets, exoplanets and free-floating planets. These turn-off point diagrams serve as an alternative to the Hertzsprung-Russell (HR) diagram, but for planets. △ Less

Submitted 2 February, 2026; v1 submitted 19 June, 2025; originally announced June 2025.

Comments: 17 pages, 9 figures

Movie Gen: A Cast of Media Foundation Models

Authors: Adam Polyak, Amit Zohar, Andrew Brown, Andros Tjandra, Animesh Sinha, Ann Lee, Apoorv Vyas, Bowen Shi, Chih-Yao Ma, Ching-Yao Chuang, David Yan, Dhruv Choudhary, Dingkang Wang, Geet Sethi, Guan Pang, Haoyu Ma, Ishan Misra, Ji Hou, Jialiang Wang, Kiran Jagadeesh, Kunpeng Li, Luxin Zhang, Mannat Singh, Mary Williamson, Matt Le , et al. (63 additional authors not shown)

Abstract: We present Movie Gen, a cast of foundation models that generates high-quality, 1080p HD videos with different aspect ratios and synchronized audio. We also show additional capabilities such as precise instruction-based video editing and generation of personalized videos based on a user's image. Our models set a new state-of-the-art on multiple tasks: text-to-video synthesis, video personalization,… ▽ More We present Movie Gen, a cast of foundation models that generates high-quality, 1080p HD videos with different aspect ratios and synchronized audio. We also show additional capabilities such as precise instruction-based video editing and generation of personalized videos based on a user's image. Our models set a new state-of-the-art on multiple tasks: text-to-video synthesis, video personalization, video editing, video-to-audio generation, and text-to-audio generation. Our largest video generation model is a 30B parameter transformer trained with a maximum context length of 73K video tokens, corresponding to a generated video of 16 seconds at 16 frames-per-second. We show multiple technical innovations and simplifications on the architecture, latent spaces, training objectives and recipes, data curation, evaluation protocols, parallelization techniques, and inference optimizations that allow us to reap the benefits of scaling pre-training data, model size, and training compute for training large scale media generation models. We hope this paper helps the research community to accelerate progress and innovation in media generation models. All videos from this paper are available at https://go.fb.me/MovieGenResearchVideos. △ Less

Submitted 26 February, 2025; v1 submitted 17 October, 2024; originally announced October 2024.

The Llama 3 Herd of Models

Authors: Aaron Grattafiori, Abhimanyu Dubey, Abhinav Jauhri, Abhinav Pandey, Abhishek Kadian, Ahmad Al-Dahle, Aiesha Letman, Akhil Mathur, Alan Schelten, Alex Vaughan, Amy Yang, Angela Fan, Anirudh Goyal, Anthony Hartshorn, Aobo Yang, Archi Mitra, Archie Sravankumar, Artem Korenev, Arthur Hinsvark, Arun Rao, Aston Zhang, Aurelien Rodriguez, Austen Gregerson, Ava Spataru, Baptiste Roziere , et al. (536 additional authors not shown)

Abstract: Modern artificial intelligence (AI) systems are powered by foundation models. This paper presents a new set of foundation models, called Llama 3. It is a herd of language models that natively support multilinguality, coding, reasoning, and tool usage. Our largest model is a dense Transformer with 405B parameters and a context window of up to 128K tokens. This paper presents an extensive empirical… ▽ More Modern artificial intelligence (AI) systems are powered by foundation models. This paper presents a new set of foundation models, called Llama 3. It is a herd of language models that natively support multilinguality, coding, reasoning, and tool usage. Our largest model is a dense Transformer with 405B parameters and a context window of up to 128K tokens. This paper presents an extensive empirical evaluation of Llama 3. We find that Llama 3 delivers comparable quality to leading language models such as GPT-4 on a plethora of tasks. We publicly release Llama 3, including pre-trained and post-trained versions of the 405B parameter language model and our Llama Guard 3 model for input and output safety. The paper also presents the results of experiments in which we integrate image, video, and speech capabilities into Llama 3 via a compositional approach. We observe this approach performs competitively with the state-of-the-art on image, video, and speech recognition tasks. The resulting models are not yet being broadly released as they are still under development. △ Less

Submitted 23 November, 2024; v1 submitted 31 July, 2024; originally announced July 2024.

Optical Spectroscopy of Classical Be Stars in Old Open Clusters

Authors: Madhu Kashyap Jagadeesh, Blesson Mathew, K. T. Paul, Gourav Banerjee, Suman Bhattacharyya, R. Anusha, Pramod Kumar S

Abstract: We performed the optical spectroscopy of 16 classical Be stars in 11 open clusters older than 100 Myr. Ours is the first spectroscopic study of classical Be stars in open clusters older than 100 Myr. We found that the H alpha emission strength of most of the stars is less than 40 Angstrom, in agreement with previous studies. Our analysis further suggests that one of the stars, KW97 35 12, might be… ▽ More We performed the optical spectroscopy of 16 classical Be stars in 11 open clusters older than 100 Myr. Ours is the first spectroscopic study of classical Be stars in open clusters older than 100 Myr. We found that the H alpha emission strength of most of the stars is less than 40 Angstrom, in agreement with previous studies. Our analysis further suggests that one of the stars, KW97 35 12, might be a weak H alpha emitter in nature, showing H alpha equivalent width of negative 0.5 Angstrom. Interestingly, we also found that the newly detected classical Be star LS III 47 37b might be a component of the possible visual binary system LS III 47 37, where the other companion is also a classical Be star. Hence, the present study indicates the possible detection of a binary Be system. Moreover, it is observed that all 16 stars exhibit a lesser number of emission lines compared to classical Be stars younger than 100 Myr. Furthermore, the spectral type distribution analysis of B type and classical Be stars for the selected clusters points out that the existence of CBe stars can depend on the spectral type distribution of B type stars present in these clusters. △ Less

Submitted 15 March, 2024; originally announced March 2024.

JPPF: Multi-task Fusion for Consistent Panoptic-Part Segmentation

Authors: Shishir Muralidhara, Sravan Kumar Jagadeesh, René Schuster, Didier Stricker

Abstract: Part-aware panoptic segmentation is a problem of computer vision that aims to provide a semantic understanding of the scene at multiple levels of granularity. More precisely, semantic areas, object instances, and semantic parts are predicted simultaneously. In this paper, we present our Joint Panoptic Part Fusion (JPPF) that combines the three individual segmentations effectively to obtain a panop… ▽ More Part-aware panoptic segmentation is a problem of computer vision that aims to provide a semantic understanding of the scene at multiple levels of granularity. More precisely, semantic areas, object instances, and semantic parts are predicted simultaneously. In this paper, we present our Joint Panoptic Part Fusion (JPPF) that combines the three individual segmentations effectively to obtain a panoptic-part segmentation. Two aspects are of utmost importance for this: First, a unified model for the three problems is desired that allows for mutually improved and consistent representation learning. Second, balancing the combination so that it gives equal importance to all individual results during fusion. Our proposed JPPF is parameter-free and dynamically balances its input. The method is evaluated and compared on the Cityscapes Panoptic Parts (CPP) and Pascal Panoptic Parts (PPP) datasets in terms of PartPQ and Part-Whole Quality (PWQ). In extensive experiments, we verify the importance of our fair fusion, highlight its most significant impact for areas that can be further segmented into parts, and demonstrate the generalization capabilities of our design without fine-tuning on 5 additional datasets. △ Less

Submitted 30 November, 2023; originally announced November 2023.

Comments: Accepted for Springer Nature Computer Science. arXiv admin note: substantial text overlap with arXiv:2212.07671

Multi-task Fusion for Efficient Panoptic-Part Segmentation

Authors: Sravan Kumar Jagadeesh, René Schuster, Didier Stricker

Abstract: In this paper, we introduce a novel network that generates semantic, instance, and part segmentation using a shared encoder and effectively fuses them to achieve panoptic-part segmentation. Unifying these three segmentation problems allows for mutually improved and consistent representation learning. To fuse the predictions of all three heads efficiently, we introduce a parameter-free joint fusion… ▽ More In this paper, we introduce a novel network that generates semantic, instance, and part segmentation using a shared encoder and effectively fuses them to achieve panoptic-part segmentation. Unifying these three segmentation problems allows for mutually improved and consistent representation learning. To fuse the predictions of all three heads efficiently, we introduce a parameter-free joint fusion module that dynamically balances the logits and fuses them to create panoptic-part segmentation. Our method is evaluated on the Cityscapes Panoptic Parts (CPP) and Pascal Panoptic Parts (PPP) datasets. For CPP, the PartPQ of our proposed model with joint fusion surpasses the previous state-of-the-art by 1.6 and 4.7 percentage points for all areas and segments with parts, respectively. On PPP, our joint fusion outperforms a model using the previous top-down merging strategy by 3.3 percentage points in PartPQ and 10.5 percentage points in PartPQ for partitionable classes. △ Less

Submitted 19 December, 2022; v1 submitted 15 December, 2022; originally announced December 2022.

Comments: Accepted in ICPRAM 2023

Study of Classical Be stars in open clusters older than 100 Myr

Authors: Madhu Kashyap Jagadeesh, Blesson Mathew, K. T. Paul, Gourav Banerjee, Annapurni Subramaniam, R. Arun

Abstract: We performed the slitless spectroscopic survey to identify Classical (CBe) stars in open clusters older than 100 Myr. Observing a sample of 71 open clusters, we identified 13 CBe stars in 11 open clusters, one of, which (TYC 2679-432-1) is a new detection. The 13 CBe stars show both H$α$ in emission and IR excess, which confirm that they possess gaseous circumstellar discs. Two more CBe stars are… ▽ More We performed the slitless spectroscopic survey to identify Classical (CBe) stars in open clusters older than 100 Myr. Observing a sample of 71 open clusters, we identified 13 CBe stars in 11 open clusters, one of, which (TYC 2679-432-1) is a new detection. The 13 CBe stars show both H$α$ in emission and IR excess, which confirm that they possess gaseous circumstellar discs. Two more CBe stars are found to exhibit H$α$ in absorption for the first time, indicating that might be passing through disc-less episode presently. The spectral type estimation is done for all these 15 stars and it is noticed that they belong to B0.5 -- B8 type. Moreover, we found that the distribution of our sample is peaking near late B-types as expected. △ Less

Submitted 1 April, 2022; originally announced April 2022.

Comments: 14 pages, 3 tables, 7 figures, appeared in Journal of Astrophysics and Astronomy

Habitability Models for Astrobiology

Authors: Abel Méndez, Edgard E. Rivera-Valentín, Dirk Schulze-Makuch, Justin Filiberto, Ramses M. Ramírez, Tana Wood, Alfonso Dávila, Chris McKay, Kevin N. Ortiz Ceballos, Marcos Jusino-Maldonado, Nicole J. Torres-Santiago, Guillermo Nery, René Heller, Paul K. Byrne, Michael J. Malaska, Erica Nathan, Marta F. Simões, André Antunes, Jesús Martínez-Frías, Ludmila Carone, Noam R. Izenberg, Dimitra Atri, Humberto I. Carvajal Chitty, Priscilla Nowajewski-Barra, Frances Rivera-Hernández , et al. (9 additional authors not shown)

Abstract: Habitability has been generally defined as the capability of an environment to support life. Ecologists have been using Habitat Suitability Models (HSMs) for more than four decades to study the habitability of Earth from local to global scales. Astrobiologists have been proposing different habitability models for some time, with little integration and consistency among them, being different in fun… ▽ More Habitability has been generally defined as the capability of an environment to support life. Ecologists have been using Habitat Suitability Models (HSMs) for more than four decades to study the habitability of Earth from local to global scales. Astrobiologists have been proposing different habitability models for some time, with little integration and consistency among them, being different in function to those used by ecologists. Habitability models are not only used to determine if environments are habitable or not, but they also are used to characterize what key factors are responsible for the gradual transition from low to high habitability states. Here we review and compare some of the different models used by ecologists and astrobiologists and suggest how they could be integrated into new habitability standards. Such standards will help to improve the comparison and characterization of potentially habitable environments, prioritize target selections, and study correlations between habitability and biosignatures. Habitability models are the foundation of planetary habitability science and the synergy between ecologists and astrobiologists is necessary to expand our understanding of the habitability of Earth, the Solar System, and extrasolar planets. △ Less

Submitted 11 August, 2021; originally announced August 2021.

Comments: Published in Astrobiology, 21(8). arXiv admin note: substantial text overlap with arXiv:2007.05491

Habitability Models for Planetary Sciences

Authors: Abel Méndez, Edgard G. Rivera-Valentín, Dirk Schulze-Makuch, Justin Filiberto, Ramses Ramírez, Tana E. Wood, Alfonso Dávila, Chris McKay, Kevin Ortiz Ceballos, Marcos Jusino-Maldonado, Guillermo Nery, René Heller, Paul Byrne, Michael J. Malaska, Erica Nathan, Marta Filipa Simões, André Antunes, Jesús Martínez-Frías, Ludmila Carone, Noam R. Izenberg, Dimitra Atri, Humberto Itic Carvajal Chitty, Priscilla Nowajewski-Barra, Frances Rivera-Hernández, Corine Brown , et al. (10 additional authors not shown)

Abstract: Habitability has been generally defined as the capability of an environment to support life. Ecologists have been using Habitat Suitability Models (HSMs) for more than four decades to study the habitability of Earth from local to global scales. Astrobiologists have been proposing different habitability models for some time, with little integration and consistency between them and different in func… ▽ More Habitability has been generally defined as the capability of an environment to support life. Ecologists have been using Habitat Suitability Models (HSMs) for more than four decades to study the habitability of Earth from local to global scales. Astrobiologists have been proposing different habitability models for some time, with little integration and consistency between them and different in function to those used by ecologists. In this white paper, we suggest a mass-energy habitability model as an example of how to adapt and expand the models used by ecologists to the astrobiology field. We propose to implement these models into a NASA Habitability Standard (NHS) to standardize the habitability objectives of planetary missions. These standards will help to compare and characterize potentially habitable environments, prioritize target selections, and study correlations between habitability and biosignatures. Habitability models are the foundation of planetary habitability science. The synergy between the methods used by ecologists and astrobiologists will help to integrate and expand our understanding of the habitability of Earth, the Solar System, and exoplanets. △ Less

Submitted 14 July, 2020; v1 submitted 10 July, 2020; originally announced July 2020.

Comments: White Paper for the Planetary Science and Astrobiology Decadal Survey 2023-2032

Journal ref: (2021) Bulletin of the American Astronomical Society, Vol. 53, Issue 4, e-id. 065

Indexing Exoplanets with Physical Conditions Potentially Suitable for Rock-Dependent Extremophiles

Authors: Madhu Kashyap Jagadeesh, Sagarika Rao Valluri, Vani Kari, Katarzyna Kubska, Łukasz Kaczmarek

Abstract: The search for different life forms elsewhere in the universe is a fascinating area of research in astrophysics and astrobiology. Currently, according to the NASA Exoplanet Archive database, 3876 exoplanets have been discovered. The Earth Similarity Index (ESI) is defined as the geometric mean of radius, density, escape velocity, and surface temperature and ranges from 0 (dissimilar to Earth) to 1… ▽ More The search for different life forms elsewhere in the universe is a fascinating area of research in astrophysics and astrobiology. Currently, according to the NASA Exoplanet Archive database, 3876 exoplanets have been discovered. The Earth Similarity Index (ESI) is defined as the geometric mean of radius, density, escape velocity, and surface temperature and ranges from 0 (dissimilar to Earth) to 1 (similar to Earth). The ESI was created to index exoplanets on the basis of their similarity to Earth. In this paper, we examined rocky exoplanets whose physical conditions are potentially suitable for the survival of rock-dependent extremophiles, such as the cyanobacteria Chroococcidiopsis and the lichen Acarospora. The Rock Similarity Index (RSI) is first introduced and then applied to 1659 rocky exoplanets. The RSI represents a measure for Earth-like planets on which physical conditions are potentially suitable for rocky extremophiles that can survive in Earth-like extreme habitats (i.e., hot deserts and cold, frozen lands). △ Less

Submitted 28 February, 2020; originally announced February 2020.

Journal ref: LIFE, 2020

Boundary conditions for similarity Index

Authors: Madhu Kashyap Jagadeesh, Purusharth Saxena

Abstract: The recent development, shows that the Bray-Curtis's formula for similarity Index (1957), has been applied in various fields like Ecology, Astrophysics, etc. In this paper, we found the possible boundary conditions for this evolved formula (i.e. the numerical range in which the formula becomes in-effective to give the expected result). Here we have simulated the real world data in the form of norm… ▽ More The recent development, shows that the Bray-Curtis's formula for similarity Index (1957), has been applied in various fields like Ecology, Astrophysics, etc. In this paper, we found the possible boundary conditions for this evolved formula (i.e. the numerical range in which the formula becomes in-effective to give the expected result). Here we have simulated the real world data in the form of normally distributed random numbers, that directly shows the range (or conditions) at which this formula gives unambiguous similarity result. △ Less

Submitted 12 June, 2018; v1 submitted 29 May, 2018; originally announced June 2018.

Earth-like and Tardigrade survey of exoplanets

Authors: Madhu Kashyap Jagadeesh, Milena Roszkowska, Lukasz Kaczmarek

Abstract: Finding life on other worlds is a fascinating area of astrobiology and planetary sciences. Presently, over 3500 exoplanets, representing a very wide range of physical and chemical environments, are known. Tardigrades (water bears) are microscopic invertebrates that inhabit almost all terrestrial, freshwater and marine habitats, from the highest mountains to the deepest oceans. Thanks to their ab… ▽ More Finding life on other worlds is a fascinating area of astrobiology and planetary sciences. Presently, over 3500 exoplanets, representing a very wide range of physical and chemical environments, are known. Tardigrades (water bears) are microscopic invertebrates that inhabit almost all terrestrial, freshwater and marine habitats, from the highest mountains to the deepest oceans. Thanks to their ability to live in a state of cryptobiosis, which is known to be an adaptation to unpredictably fluctuating environmental conditions, these organisms are able to survive when conditions are not suitable for active life; consequently, tardigrades are known as the toughest animals on Earth. In their cryptobiotic state, they can survive extreme conditions, such as temperatures below -250°C and up to 150°C, high doses of ultraviolet and ionising radiation, up to 30 years without liquid water, low and high atmospheric pressure, and exposure to many toxic chemicals. Active tardigrades are also resistant to a wide range of unfavourable environmental conditions, which makes them an excellent model organism for astrobiological studies. In our study, we have established a metric tool for distinguishing the potential survivability of active and cryptobiotic tardigrades on rocky-water and water-gas planets in our solar system and exoplanets, taking into consideration the geometrical means of surface temperature and surface pressure of the considered planets. The Active Tardigrade Index (ATI) and Cryobiotic Tardigrade Index (CTI) are two metric indices with minimum value 0 (= tardigrades cannot survive) and maximum 1 (= tardigrades will survive in their respective state). Values between 0 and 1 indicate a percentage chance of the active or cryptobiotic tardigrades surviving on a given exoplanet. △ Less

Submitted 6 June, 2018; v1 submitted 7 February, 2018; originally announced February 2018.

Journal ref: Life Sciences in Space Rsearch 2018

Earth Similarity Index and Habitability Studies of Exoplanets

Authors: Madhu Kashyap Jagadeesh

Abstract: Study of exoplanets has been of considerable interest for Astronomers, Planetary Scientists and Astrobiologists. Analysis of huge planetary data from space missions such as CoRoT and Kepler is directed ultimately at finding a planet similar to Earth- the Earth's twin, and looking for potential habitability. The Earth Similarity Index (ESI) is defined to find the similarity with Earth, which ranges… ▽ More Study of exoplanets has been of considerable interest for Astronomers, Planetary Scientists and Astrobiologists. Analysis of huge planetary data from space missions such as CoRoT and Kepler is directed ultimately at finding a planet similar to Earth- the Earth's twin, and looking for potential habitability. The Earth Similarity Index (ESI) is defined to find the similarity with Earth, which ranges from 1 (Earth) to 0 (totally dissimilar to Earth). ESI can be computed using four physical parameters of a planet, namely radius, density, escape velocity and surface temperature. The surface temperature entering surface ESI is a non-observable quantity and what we know is only equilibrium temperature of exoplanets. We have established a relation between surface and equilibrium temperatures using the data available for the solar system objects to address the difficulty in determining surface temperature. From the ESI analysis, we have found 20 Earth-like exoplanets with ESI value above 0.8, which is set as the threshold. We are also interested in Mars-like planets to search for planets that may host the extreme life For example, methane-specific extremophile life form metabolism, for which a new approach, called Mars Similarity Index (MSI) is introduced. MSI is defined in the range between 1 (present Mars) and 0 (dissimilar to present Mars) and uses the same physical parameters as that of ESI. We introduced another new approach to study the potential habitability of exoplanets based on Cobb-Douglas Function, multi-parametric function. This did not yield any encouraging results. △ Less

Submitted 6 June, 2018; v1 submitted 22 January, 2018; originally announced January 2018.

Comments: Thesis

Extremophile life-form survey on rocky exoplanets

Authors: Madhu Kashyap Jagadeesh

Abstract: Search for different life-forms elsewhere is the fascinating area of research in astrophysics and astrobiology. Nearly 3500 exoplanets are discovered according to NASA exoplanet archive database. Earth Similarity Index (ESI) is defined as the geometrical mean of radius, density, escape velocity and surface temperature, ranging from 0 (dissimilar to Earth) to 1(Earth). In this research, rocky exopl… ▽ More Search for different life-forms elsewhere is the fascinating area of research in astrophysics and astrobiology. Nearly 3500 exoplanets are discovered according to NASA exoplanet archive database. Earth Similarity Index (ESI) is defined as the geometrical mean of radius, density, escape velocity and surface temperature, ranging from 0 (dissimilar to Earth) to 1(Earth). In this research, rocky exoplanets that are suitable for rock dependent extremophiles, such as: Chroococcidiopsis and Acarosporamto are chosen, which can potentially survive are considered. The Colonizing Similarity Index (CSI) is introduced and analysed for 1650 rocky exoplanets, CSI is basically representing Earth-like planets that are suitable for rocky extremophiles which can survive in extreme temperatures (i.e. as hot as desert and cold as frozen lands). In this work the in-habitable exoplanets are recognised even for these rocky extremophiles to not potentially survive by using the CSI metric tool. △ Less

Submitted 29 May, 2018; v1 submitted 19 January, 2018; originally announced January 2018.

Similarity indexing of exoplanets in search for potential habitability: application to Mars-like worlds

Authors: Madhu Kashyap Jagadeesh, S. B. Gudennavar, Urmi Doshi, M. Safonova

Abstract: Study of exoplanets is one of the main goals of present research in planetary sciences and astrobiology. Analysis of huge planetary data from space missions such as CoRoT and Kepler is directed ultimately at finding a planet similar to Earth -- the Earth's twin, and answering the question of potential exo-habitability. The Earth Similarity Index (ESI) is a first step in this quest, ranging from… ▽ More Study of exoplanets is one of the main goals of present research in planetary sciences and astrobiology. Analysis of huge planetary data from space missions such as CoRoT and Kepler is directed ultimately at finding a planet similar to Earth -- the Earth's twin, and answering the question of potential exo-habitability. The Earth Similarity Index (ESI) is a first step in this quest, ranging from 1 (Earth) to 0 (totally dissimilar to Earth). It was defined for the four physical parameters of a planet: radius, density, escape velocity and surface temperature. The ESI is further sub-divided into interior ESI (geometrical mean of radius and density) and surface ESI (geometrical mean of escape velocity and surface temperature). The challenge here is to determine which exoplanet parameter(s) is important in finding this similarity; how exactly the individual parameters entering the interior ESI and surface ESI are contributing to the global ESI. Since the surface temperature entering surface ESI is a non-observable quantity, it is difficult to determine its value. Using the known data for the Solar System objects, we established the calibration relation between surface and equilibrium temperatures to devise an effective way to estimate the value of the surface temperature of exoplanets for further analysis with our graphic methodology. A new approach, called Mars Similarity Index (MSI), is introduced to identify planets that may be habitable to the extreme forms of life. MSI is defined in the range between 1 (present Mars) and 0 (dissimilar to present Mars) and uses the same physical parameters as ESI. We are interested in Mars-like planets to search for planets that may host the extreme life forms, such as the ones living in extreme environments on Earth; for example, methane on Mars may be a product of the methane-specific extremophile life form metabolism. △ Less

Submitted 6 June, 2018; v1 submitted 24 August, 2016; originally announced August 2016.

Comments: 14 pages

Journal ref: Astrophysics and Space Science 2017