%0 Journal Article
%T Detection of Fe£¿I and Fe£¿II in the atmosphere of MASCARA-2b using a cross-correlation method
%A A. S¨¢nchez-L¨®pez
%A E. Pall¨¦
%A F. Yan
%A M. L¨®pez-Puertas
%A M. Stangret
%A N. Casasayas-Barris
%J -
%D 2020
%R 10.1051/0004-6361/202037541
%X Ultra-hot Jupiters are gas giants planets whose dayside temperature is greater than 2200 K as a consequence of the strong irradiation received from the host star. These kinds of objects are perfect laboratories to study the chemistry of exoplanetary upper atmospheres via transmission spectroscopy. Exo-atmospheric absorption features are buried in the noise of the in-transit residual spectra. However we can retrieve information of hundreds of atmospheric absorption lines by performing a cross-correlation with an atmospheric transmission model, which allows us to greatly increase the exo-atmospheric signal. The Rossiter¨CMcLaughlin effect and centre-to-limb variation contribute strongly at the high spectral resolution of our data. We present the first detection of Fe£¿I and confirmation of absorption features of Fe£¿II in the atmosphere of the ultra-hot Jupiter MASCARA-2b/KELT-20b, by using three transit observations with HARPS-N. After combining all transit observations we find a high cross-correlation signal of Fe£¿I and Fe£¿II with signal-to-noise ratios of 10.5 ¡À 0.4 and 8.6 ¡À 0.5, respectively. The peak absorption for both species appear to be blue-shifted with velocities of £¿ 6.3 ¡À 0.8 km s<sup>£¿1<sup/> for Fe£¿I and £¿ 2.8 ¡À 0.8 km s<sup>£¿1<sup/> for Fe£¿II, suggesting the presence of winds from the day- to night-side of the atmosphere of the planet. These results confirm previous studies of this planet and add a new atomic species (Fe£¿I) to the long list of detected species in the atmosphere of MASCARA-2b, making it, together with KELT-9b, the most feature-rich ultra-hot Jupiter to date
%U https://www.aanda.org/articles/aa/full_html/2020/06/aa37541-20/aa37541-20.html