[Imagerie directe des exoplanètes : Héritage et perspectives]
Comprendre comment les planètes géantes et terrestres se forment et évoluent, quelle est leur structure interne et celle de leur atmosphère, représente l’un des défis majeurs de l’astronomie moderne, qui est directement lié à la recherche ultime de la vie à l’horizon 2030–2050. Cependant, plusieurs obstacles astrophysiques (compréhension de la formation et de la physique des exoplanètes géantes et terrestres), biologiques (identification des meilleurs biomarqueurs) et technologiques (innovations techniques pour les nouvelles générations de télescopes et d’instruments) doivent être surmontés. Du point de vue astrophysique, il est en effet crucial de comprendre les mécanismes de formation et d’évolution des planètes géantes, y compris les interactions entre la planète et le disque, qui vont complètement sculpter les architectures planétaires et ainsi dominer la formation de planètes terrestres, notamment dans les régions autour de l’étoile hôte capables d’accueillir la vie. Il est également important de développer une instrumentation et des techniques dédiées pour étudier dans leur totalité la population de planètes géantes et terrestres, mais aussi de révéler dans un futur proche les premiers marqueurs biologiques de la vie dans les atmosphères des planètes terrestres. Dans cette perspective, l’imagerie directe depuis des observatoires au sol ou dans l’espace joue un rôle central, de concert avec d’autres techniques d’observation. Dans cet article, je rappellerai brièvement la genèse de cette technique d’observation, les principales innovations et défis instrumentaux, les cibles stellaires et les relevés, pour ensuite présenter les principaux résultats obtenus jusqu’à présent sur la physique et les mécanismes de formation et dévolution des jeunes planètes géantes et les architectures des systèmes planétaires. Je présenterai ensuite les perspectives passionnantes offertes par la prochaine génération d’imageurs de planètes sur le point d’être mis en ligne, notamment sur les futurs extrêmement grands télescopes. A l’échelle d’une vie humaine, nous pourrions bien assister à la première découverte d’une exoplanète et à la première détection d’indices de vie dans l’atmosphère d’une exo-Terre proche !
Understanding how giant and terrestrial planets form and evolve, what is their internal structure and that of their atmosphere, represents one of the major challenges of modern astronomy, which is directly connected to the ultimate search for life at the horizon 2030–2050. However, several astrophysical (understanding of the formation and physics of giant and terrestrial exoplanets), biological (identification of the best biomarkers) and technological (technical innovations for the new generations of telescopes and instruments) obstacles must be overcome. From the astrophysical point of view, it is indeed crucial to understand the mechanisms of formation and evolution of giant planets, including planet and disk interactions, which will completely sculpt the planetary architectures and thus dominate the formation of terrestrial planets, especially in regions around the host star capable of supporting life. It is also important to develop dedicated instrumentation and techniques to study in their totality the population of giant and terrestrial planets, but also to reveal in the near future the first biological markers of life in the atmospheres of terrestrial planets. In that perspective, direct imaging from ground-based observatories or in space is playing a central role in concert with other observing techniques. In this paper, I will briefly review the genesis of this observing technique, the main instrumental innovation and challenges, stellar targets and surveys, to then present the main results obtained so far about the physics and the mechanisms of formation and evolution of young giant planets and planetary system architectures. I will then present the exciting perspectives offered by the upcoming generation of planet imagers about to come online, particularly on the future extremely large telescopes. On the timescale of a human Life, we may well be witnessing the first discovery of an exoplanet and the first detection of indices of life in the atmosphere of a nearby exo-Earth!
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Mot clés : Exoplanètes, Systèmes planétaires, Atmosphère, Architecture, Imagerie directe, Spectroscopie
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@article{CRPHYS_2023__24_S2_A12_0,
author = {Gael Chauvin},
title = {Direct imaging of exoplanets: {Legacy} and prospects},
journal = {Comptes Rendus. Physique},
publisher = {Acad\'emie des sciences, Paris},
year = {2023},
doi = {10.5802/crphys.139},
language = {en},
note = {Online first},
}
Gael Chauvin. Direct imaging of exoplanets: Legacy and prospects. Comptes Rendus. Physique, Online first (2023), pp. 1-22. doi : 10.5802/crphys.139.
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