Transmission spectroscopy with VLT FORS2: a featureless spectrum for the low-density transiting exoplanet WASP-88b [EPA]

http://arxiv.org/abs/2106.14808


We present ground-based optical transmission spectroscopy of the low-density hot Jupiter WASP-88b covering the wavelength range 4413-8333 {\AA} with the FORS2 spectrograph on the Very Large Telescope. The FORS2 white light curves exhibit a significant time-correlated noise which we model using a Gaussian Process and remove as a wavelength-independent component from the spectroscopic light curves. We analyse complementary photometric observations from the Transiting Exoplanet Survey Satellite and refine the system properties and ephemeris. We find a featureless transmission spectrum with increased absorption towards shorter wavelengths. We perform an atmospheric retrieval analysis with the AURA code, finding tentative evidence for haze in the upper atmospheric layers and a lower likelihood for a dense cloud deck. Whilst our retrieval analysis results point toward clouds and hazes, further evidence is needed to definitively reject a clear-sky scenario.

Read this paper on arXiv…

P. Spyratos, N. Nikolov, J. Southworth, et. al.
Tue, 29 Jun 21
46/101

Comments: 19 pages, 12 figures, 3 tables, Accepted for publication in MNRAS