Séminaire Doctorants / Seminar PhD students |
| « Small planets atmospheric characterization with Hubble: application to TRAPPIST-1 h » |
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Amélie Gressier |
| Small planets atmospheric characterization remains challenging with present time observations but every analysis is crucial in our quest of life in the Galaxy. The very famous TRAPPIST-1 planetary system is favourable for transmission spectroscopy and offers the unique opportunity to study rocky planets with possibly non-primary envelopes in the habitable zone. I will present the transmission spectrum of the seventh planet of the TRAPPIST-1 system, TRAPPIST-1 h (RP=0.752 R?, Teq=173K) using Hubble Space Telescope (HST), Wide Field Camera 3 Grism 141 (WFC3/G141) data. We extracted and corrected the raw data to obtain a transmission spectrum in the near-infrared (NIR) band (1.1-1.7µm). TRAPPIST-1 is a cold M-dwarf and its activity could affect the transmission spectrum. We corrected for stellar modulations using three different stellar contamination models, and, using a Bayesian atmospheric retrieval code, we put new constraints on the atmospheric composition. To put this observation into perspective, I will present the first results of a Hubble transmission survey on Super-Earth and Sub-Neptune. While HST gives a first insight into small planets atmospheres it is still impossible to differentiate primary and secondary envelopes. This results in biases in the retrieval analysis but could be solved with ARIEL observations. |
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vendredi 11 mars 2022 - 16:00 Salle des séminaires Évry Schatzman, Institut d'Astrophysique |
| Page web du Séminaire / Seminar's webpage |