The Complete Transmission Spectrum of WASP-39b with a Precise Water Constraint
AuthorWakeford, H. R.
Sing, D. K.
Lewis, N. K.
Wilson, T. J.
Evans, T. M.
Carter, A. L.
Knutson, H. A.
Ballester, G. E.
Mandell, A. M.
AffiliationUniv Arizona, Lunar & Planetary Lab
Keywordsplanets and satellites: atmospheres
planets and satellites: individual (WASP-39b)
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationThe Complete Transmission Spectrum of WASP-39b with a Precise Water Constraint 2017, 155 (1):29 The Astronomical Journal
JournalThe Astronomical Journal
Rights© 2017. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractWASP-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 mu m) and G141 (1.1-1.7 mu m) spectroscopic grisms. We measure the predicted high-amplitude H2O feature centered at 1.4 mu m and the smaller amplitude features at 0.95 and 1.2 mu m, 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 mu m. 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) 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.
VersionFinal published version
SponsorsEuropean Research Council (ERC) under the European Unions Seventh Framework Programme (FP7)/ERC grant ; Leverhulme Trust; STFC; Giacconi Fellowship at the Space Telescope Science Institute by the Association of Universities for Research in Astronomy, Inc.; [GO-14169]; [GO-14260]