Volume 638, June 2020
|Number of page(s)
|Planets and planetary systems
|04 June 2020
Detection of Fe I and Fe II in the atmosphere of MASCARA-2b using a cross-correlation method
Instituto de Astrofísica de Canarias,
Vía Láctea s/n,
2 Departamento de Astrofísica, Universidad de La Laguna, 38200 San Cristobal de La Laguna, Spain
3 Institut für Astrophysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
4 Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain
Accepted: 27 February 2020
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–McLaughlin 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 ± 0.4 and 8.6 ± 0.5, respectively. The peak absorption for both species appear to be blue-shifted with velocities of − 6.3 ± 0.8 km s−1 for Fe I and − 2.8 ± 0.8 km s−1 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.
Key words: planetary systems / planets and satellites: individual: MASCARA2-b / planets and satellites: atmospheres / techniques: spectroscopic
© ESO 2020
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.