Detection Of Na, K And H2O In The Hazy Atmosphere Of WASP-6b

Representative observed spectra for the FORS2 G600B, FORS2 G600RI and WFC3 G141 grisms, the thicker coloured lines indicate spectra of WASP-6 whilst thinner grey lines correspond to that of the reference star. Shaded bands indicate the selected wavelength binning for each grism.

We present new observations of the transmission spectrum of the hot Jupiter WASP-6b both from the ground with the Very Large Telescope (VLT) FOcal Reducer and Spectrograph (FORS2) from 0.45-0.83 μm, and space with the Transiting Exoplanet Survey Satellite (TESS) from 0.6-1.0 μm and the Hubble Space Telescope (HST) Wide Field Camera 3 from 1.12-1.65 μm.

Archival data from the HST Space Telescope Imaging Spectrograph (STIS) and Spitzer is also reanalysed on a common Gaussian process framework, of which the STIS data show a good overall agreement with the overlapping FORS2 data. We also explore the effects of stellar heterogeneity on our observations and its resulting implications towards determining the atmospheric characteristics of WASP-6b.

Independent of our assumptions for the level of stellar heterogeneity we detect Na I, K I and H2O absorption features and constrain the elemental oxygen abundance to a value of [O/H] ≃−0.9±0.3 relative to solar. In contrast, we find that the stellar heterogeneity correction can have significant effects on the retrieved distributions of the [Na/H] and [K/H] abundances, primarily through its degeneracy with the sloping optical opacity of scattering haze species within the atmosphere. Our results also show that despite this presence of haze, WASP-6b remains a favourable object for future atmospheric characterisation with upcoming missions such as the James Webb Space Telescope.

Aarynn L. Carter, Nikolay Nikolov, David K. Sing, Munazza K. Alam, Jayesh M. Goyal, Thomas Mikal-Evans, Hannah R. Wakeford, Gregory W. Henry, Sam Morrell, Mercedes López-Morales, Barry Smalley, Panayotis Lavvas, Joanna K. Barstow, Antonio García Muñoz, Paul A. Wilson, Neale P. Gibson
(Submitted on 28 Nov 2019)

Comments: Submitted to MNRAS
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:1911.12628 [astro-ph.EP] (or arXiv:1911.12628v1 [astro-ph.EP] for this version)
Submission history
From: Aarynn Carter Mr
[v1] Thu, 28 Nov 2019 10:26:03 UTC (7,764 KB)
https://arxiv.org/abs/1911.12628
Astrobiology, astrochemistry

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