Nikolov, N;
Sing, D;
Gibson, N;
Fortney, J;
Evans, TM;
Eberhardt, JK;
Kataria, T;
(2016)
VLT FORS2 comparative transmission spectroscopy: Detection of Na in the atmosphere of WASP-39b from the ground.
The Astrophysical Journal
, 832
(2)
, Article 191. 10.3847/0004-637X/832/2/191.
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Abstract
We present transmission spectroscopy of the warm Saturn-mass exoplanet WASP-39b made with the Very Large Telescope FOcal Reducer and Spectrograph (FORS2) across the wavelength range 411–810 nm. The transit depth is measured with a typical precision of 240 parts per million (ppm) in wavelength bins of 10 nm on a V = 12.1 mag star. We detect the sodium absorption feature (3.2σ) and find evidence of potassium. The ground-based transmission spectrum is consistent with Hubble Space Telescope (HST) optical spectroscopy, supporting the interpretation that WASP-39b has a largely clear atmosphere. Our results demonstrate the great potential of the recently upgraded FORS2 spectrograph for optical transmission spectroscopy, with which we obtained HST-quality light curves from the ground.
Type: | Article |
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Title: | VLT FORS2 comparative transmission spectroscopy: Detection of Na in the atmosphere of WASP-39b from the ground |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.3847/0004-637X/832/2/191 |
Publisher version: | http://doi.org/10.3847/0004-637X/832/2/191 |
Language: | English |
Additional information: | © 2016. The American Astronomical Society. All rights reserved. |
Keywords: | Planets and satellites: atmospheres; stars: individual (WASP-39); techniques: photometric; techniques: spectroscopic |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences |
URI: | https://discovery.ucl.ac.uk/id/eprint/1529980 |
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