Issue |
A&A
Volume 573, January 2015
|
|
---|---|---|
Article Number | A11 | |
Number of page(s) | 4 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/201323266 | |
Published online | 08 December 2014 |
Research Note
The Mg i line: a new probe of the atmospheres of evaporating exoplanets
1
CNRS, UMR 7095, Institut d’astrophysique de Paris,
98bis boulevard Arago,
75014
Paris,
France
e-mail:
bourrier@iap.fr
2
UPMC Univ. Paris 6, UMR 7095, Institut d’Astrophysique de
Paris, 98bis boulevard Arago, 75014
Paris,
France
3
Observatoire de l’Université de Genève,
51 chemin des Maillettes,
1290
Sauverny,
Switzerland
Received: 17 December 2013
Accepted: 22 October 2014
Transit observations of HD 209458b in the UV revealed signatures of neutral magnesium escaping the planet’s upper atmosphere. The absorption detected in the Mg i line provides unprecedented information on the physical conditions at the altitude where the atmospheric blow-off takes place. Here we use a 3D model of atmospheric escape to estimate the transit absorption signatures in the Mg i line of their host stars. The detectability of these signatures depends on the brightness of the star and the escape rate of neutral magnesium. We identify a sample of potentially evaporating exoplanets that covers a wide range of stellar and planetary properties, and whose extended exospheres might be detected through Mg i line observations with current UV facilities, allowing further steps in comparative exoplanetology.
Key words: surveys / planets and satellites: atmospheres / methods: numerical
© ESO, 2014
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