Volume 600, April 2017
|Number of page(s)||6|
|Published online||13 April 2017|
The GTC exoplanet transit spectroscopy survey⋆
VI. Detection of sodium in WASP-52b’s cloudy atmosphere
1 Instituto de Astrofísica de Canarias, vía Láctea s/n, 38205 La Laguna, Tenerife, Spain
2 Departamento de Astrofísica, Universidad de La Laguna, Spain
3 Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences, 210008 Nanjing, PR China
Received: 6 March 2017
Accepted: 17 March 2017
We report the first detection of sodium absorption in the atmosphere of the hot Jupiter WASP-52b. We observed one transit of WASP-52b with the low-resolution Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) at the 10.4 m Gran Telescopio Canarias (GTC). The resulting transmission spectrum, covering the wavelength range from 522 nm to 903 nm, is flat and featureless, except for the significant narrow absorption signature at the sodium doublet, which can be explained by an atmosphere in solar composition with clouds at 1 mbar. A cloud-free atmosphere is stringently ruled out. By assessing the absorption depths of sodium in various bin widths, we find that temperature increases towards lower atmospheric pressure levels, with a positive temperature gradient of 0.88 ± 0.65 K km-1, possibly indicative of upper atmospheric heating and a temperature inversion.
Key words: planetary systems / planets and satellites: individual: WASP-52b / planets and satellites: atmospheres / techniques: spectroscopic
The light curves are only vailable at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (188.8.131.52) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/600/L11
© ESO, 2017
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