Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS)

Seidel, J. V.; Ehrenreich, D.; Wyttenbach, A.; Allart, R.; Lendl, M.; Pino, L.; Bourrier, V.; Cegla, H. M.; Lovis, C.; Barrado, D.; Bayliss, D.; Astudillo-Defru, N.; Deline, A.; Fisher, C.; Heng, Kevin; Joseph, R.; Lavie, Baptiste; Melo, C.; Pepe, F.; Ségransan, D.; ... (2019). Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS). Astronomy and astrophysics, 623(A166), A166. EDP Sciences 10.1051/0004-6361/201834776

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High-resolution optical spectroscopy is a powerful tool to characterise exoplanetary atmospheres from the ground. The sodium D lines, with their large cross sections, are especially suited to study the upper layers of atmospheres in this context. We report on the results from HEARTS, a spectroscopic survey of exoplanet atmospheres, performing a comparative study of hot gas giants to determine the effects of stellar irradiation. In this second installation of the series, we highlight the detection of neutral sodium on the ultra-hot giant WASP-76b. We observed three transits of the planet using the HARPS high-resolution spectrograph at the ESO 3.6m telescope and collected 175 spectra of WASP-76. We repeatedly detect the absorption signature of neutral sodium in the planet atmosphere (0.371±0.034%; 10.75σ in a 0.75 Å passband). The sodium lines have a Gaussian profile with full width at half maximum (FWHM) of 27.6±2.8 km s⁻¹. This is significantly broader than the line spread function of HARPS (2.7 km s⁻¹). We surmise that the observed broadening could trace the super-rotation in the upper atmosphere of this ultra-hot gas giant.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute
10 Strategic Research Centers > Center for Space and Habitability (CSH)
08 Faculty of Science > Physics Institute > NCCR PlanetS

UniBE Contributor:

Fisher, Chloe Elizabeth; Heng, Kevin and Lavie, Baptiste

Subjects:

500 Science
500 Science > 520 Astronomy
500 Science > 530 Physics

ISSN:

0004-6361

Publisher:

EDP Sciences

Language:

English

Submitter:

Danielle Zemp

Date Deposited:

14 Apr 2020 14:24

Last Modified:

19 Apr 2020 02:53

Publisher DOI:

10.1051/0004-6361/201834776

ArXiv ID:

1902.00001v1

BORIS DOI:

10.7892/boris.142653

URI:

https://boris.unibe.ch/id/eprint/142653

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