Presenter: Núria CASASAYAS-BARRIS
Abstract:
Ultra-hot Jupiters are those planets with temperatures higher than 2000K because they orbit very close to their host star, receiving a large amount of irradiation in their day-side upper atmosphere. We have studied the atmosphere of one of these particular hot planets, MASCARA-2b / KELT-20b, using four transit observations with high resolution spectroscopy facilities. Three of these observations were performed with HARPS-N and one with CARMENES. Additionally, we simultaneously observed one of the transits with MuSCAT2 to monitor possible spots in the stellar surface. At high resolution, the transmission residuals show the effects of Rossiter-McLaughlin and centre- to-limb variations from the stellar lines profiles, which can modify the transmission spectra of the planet. Using the transmission spectroscopy method we clearly observe the absorption features of CaII, FeII, NaI, Hα, and Hβ in the atmosphere of MASCARA-2b, and indications of Hγ and MgI at low signal-to-noise ratio. These results are consistent with theoretical models of ultra-hot Jupiters atmospheres, suggesting the emergence of an ionised gas on the day-side of such planets.