Séminaire Exoplanètes / |
| « Characterization of Beta Pictoris exocomets using UV spectroscopy. » |
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Théo Vrignaud |
| Extrasolar comets – or exocomets – are icy bodies placed on very elliptical orbits, which sublimate as they approach their periastron and produce extensive clouds of dust and gas – the so-called ‘cometary tails’. The most famous star known to harbor such objects is Beta Pictoris, a young (~ 20 Myr) A-type star embedded in a large debris disk, for which transiting comets are routinely detected using absorption spectroscopy (which probes the gaseous part of the cometary tail) and photometry (probing the dusty part of the cometary tail). However, despite more than 35 years of observations, still very little information on the formation, history and composition of these exocomets is known. Here, I will present a new analysis of archival HST/STIS data, which led to the first measurement of the typical column density, temperature and electronic density within Beta Pictoris transiting exocomets. These first results pave the way for further study of the variable absorption features created by these objects, in order to reveal some of their key properties (e.g., C/O or dust-to-ice ratios). Such information will shed new light on the role of comets in the formation and evolution of planetary systems. |
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mardi 7 novembre 2023 - 14:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |