Detection of Na, K and H\(_2\)O in the hazy atmosphere of WASP-6b

• Published in: arXiv.org 2020-05
• Main Authors: Carter, Aarynn L, Nikolov, Nikolay, Sing, David K, Alam, Munazza K, Goyal, Jayesh M, Mikal-Evans, Thomas, Wakeford, Hannah R, Henry, Gregory W, Morrell, Sam, López-Morales, Mercedes, Smalley, Barry, Lavvas, Panayotis, Barstow, Joanna K, Antonio García Muñoz, Wilson, Paul A, Gibson, Neale P
• Format: Article
• Language: English
• Subjects: Abundance; Extrasolar planets; Field cameras; Gas giant planets; Gaussian process; Haze; Heterogeneity; Hubble Space Telescope; James Webb Space Telescope; Planet detection; Space missions; Space telescopes; Transit; Very Large Telescope
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1911.12628

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 \(\mu\)m, and space with the Transiting Exoplanet Survey Satellite (TESS) from 0.6-1.0 \(\mu\)m and the Hubble Space Telescope (HST) Wide Field Camera 3 from 1.12-1.65 \(\mu\)m. 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 H\(_2\)O absorption features and constrain the elemental oxygen abundance to a value of [O/H] \(\simeq -0.9\pm0.3\) 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.