The Study of Atmospheres of Exoplanets : Status and Perspectives
Abstract
The study of the atmospheres of exoplanets is at the verge of a new revolution. After the detection of thousands of planetary systems, most of the physical parameters obtained so far are still restricted to orbital parameters, mass and size of these objects, which is notoriously insufficient to characterize the systems due to multivalue retrievals from inverse models.Constraining the atmospheric structure and composition has been possible only for a dozen of planets, from IRAC, Spitzer, HST or ground based telescopes. The James Webb Space Telescope, to be launched in 2019, is expected to observe many more exoplanets transits and eclipses, as well as direct observations when possible, with exquisite signal to noise [1]. Today, the current knowledge of the exoplanets corpus has unveiled a large variety of systems, not known in our Solar System, which would even have been thought impossible 15 years ago: hot Jupiters, warm Neptunes, Superearths, etc. Our Solar System is definitely not the common standard for planets in the Universe, and anthropocentrism has once again be defeated, urging for more open mind approaches to understand exoplanetary systems. New missions will be needed to address this scientific goal [2]. Nevertheless the great details available from our Solar System planets is still of great use as a template to validate models before extrapolation, or as a "ground truth" model to test observation retrieval. The possibility to infer the history of Solar System atmospheres on Venus, Mars or Earth has also profound implications on the research of exoplanets. The new era of interpretation of planetary atmospheres will have to combine expertise from :
Stellar physics, to know as accurately as possible the stellar environment, activity and history of the exoplanets. Planetology : spectroscopy of planetary atmospheres has developed a corpus of expertise by 50 years of space observations on planets, including Earth, which can be deployed to study the new worlds Spectroscopy : as traditional spectroscopic databases for hot temperature molecules are challenged by the needs of exoplanet modelling, the breakthrough in spectroscopic analysis came with ab initio models accurate enough to provide complete molecular spectroscopic data for hot bands observed in the near infrared and for various molecules [3] Big data analysis : new methods of calculations including Artificial Intelligence algorithms are emerging to deal with the huge database and the complexity of models [4] The era of exoplanetology is only starting to emerge and we can expect in the next decades new revolutions in the science of planets, with new missions and instruments like the future ESA/M4 ARIEL mission [5]. [1] EXPLORING THE UNIVERSE WITH JWST: 49th ESLAB symposium, 12-16 Octobre 2015, ESTEC, Noordwijk, Pays-Bas. 2015. [2] Echo - Exoplanet Characterisation Observatory; Tinetti and Drossart editors, Springer, 2015 ISBN 978-94-024-0836-2 [3] J. Tennyson et al. The ExoMol database: Molecular line lists for exoplanet and other hot atmospheres (2016). Journal of Molecular Spectroscopy, Vol. 327, p. 73-94. [4] Ingo P. Waldmann Artificial Intelligence in planetary spectroscopy, EPSC Abstracts Vol. 11, EPSC2017-240, [5] Tinetti G. et al.,The Science of ARIEL, EPSC Abstracts Vol. 11, EPSC2017-713, 2017 European Planetary Science Congress 2017 2017 European Planetary Science Congress 2017- Publication:
-
42nd COSPAR Scientific Assembly
- Pub Date:
- July 2018
- Bibcode:
- 2018cosp...42E.894D