Séminaire IPAG

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Detection and characterization of rocky planets around ultra-cool stars

jeudi 10 octobre 2024 - 11h00

Elsa Ducrot - LESIA
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The launch of the James Webb Space Telescope (JWST) marked a significant milestone in the field of exoplanet research. For the first time, we can study the atmospheres of Earth-sized rocky planets—an opportunity that was previously unattainable. However, this is currently possible only around the coolest stars, known as red dwarfs. These stars are ideal targets for several reasons: (1) their smaller size makes it easier to detect and study small, transiting planets; (2) their lower luminosity leads to more frequent planetary transits for the same level of stellar irradiation; (3) they are the most abundant stars in the galaxy, and (4) planets orbiting them are more likely to be rocky planets with short orbital periods. In the near future, only such planetary systems are expected to produce signal-to-noise ratios (SNRs) high enough to confidently confirm or rule out the presence of atmospheres on potentially habitable planets. In this context, my research focuses on: (1) detecting new rocky, temperate planets around red dwarfs using the SPECULOOS telescopes, and (2) observing these planets with JWST to assess the presence and composition of their atmospheres or determine the nature of their surfaces. In this talk, I will share insights into these two areas of my work, including the discovery of the new SPECULOOS-3b exoplanetary system and the detailed characterization of TRAPPIST-1's innermost planets using JWST data. I will also discuss stellar contamination caused by photometric heterogeneities, which represents the primary challenge in characterizing planets around red dwarfs in transit, along with some observational strategies to overcome this obstacle. Finally, I will present some perspectives on the future study of rocky planets orbiting red dwarfs.

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Salle Manuel Forestini, 414 rue de la piscine, 38400 Saint Martin d'Hères