Wakeford, HR;
Sing, DK;
Deming, D;
Lewis, NK;
Goyal, J;
Wilson, TJ;
Barstow, J;
... Mandell, AM; + view all
(2018)
The Complete Transmission Spectrum of WASP-39b with a Precise Water Constraint.
Astronomical Journal
, 155
(1)
10.3847/1538-3881/aa9e4e.
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Abstract
WASP-39b is a hot Saturn-mass exoplanet with a predicted clear atmosphere based on observations in the optical and infrared. Here, we complete the transmission spectrum of the atmosphere with observations in the near-infrared (NIR) over three water absorption features with the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) G102 (0.8–1.1 μm) and G141 (1.1–1.7 μm) spectroscopic grisms. We measure the predicted high-amplitude H2O feature centered at 1.4 μm and the smaller amplitude features at 0.95 and 1.2 μm, with a maximum water absorption amplitude of 2.4 planetary scale heights. We incorporate these new NIR measurements into previously published observational measurements to complete the transmission spectrum from 0.3 to 5 μm. From these observed water features, combined with features in the optical and IR, we retrieve a well constrained temperature T eq = 1030${}_{-20}^{+30}$ K, and atmospheric metallicity ${151}_{-46}^{+48}\times $ solar, which is relatively high with respect to the currently established mass–metallicity trends. This new measurement in the Saturn-mass range hints at further diversity in the planet formation process relative to our solar system giants.
Type: | Article |
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Title: | The Complete Transmission Spectrum of WASP-39b with a Precise Water Constraint |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.3847/1538-3881/aa9e4e |
Publisher version: | https://doi.org/10.3847/1538-3881/aa9e4e |
Language: | English |
Additional information: | This is the published version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
Keywords: | planets and satellites: atmospheres; planets and satellites: individual (WASP-39b); 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/10041522 |
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