Transmission spectroscopy with VLT FORS2 : a featureless spectrum for the low-density transiting exoplanet WASP-88b
Abstract
We present ground-based optical transmission spectroscopy of the low-density hot Jupiter WASP-88b covering the wavelength range of 4413−8333 Å with the FOcal Reducer Spectrograph (FORS2) on the Very Large Telescope. The FORS2 white light curves exhibit a significant time-correlated noise that 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. While our retrieval analysis results point towards clouds and hazes, further evidence is needed to definitively reject a clear-sky scenario.
Citation
Spyratos , P , Nikolov , N , Southworth , J , Constantinou , S , Madhusudhan , N , Carter , A L , de Mooij , E J W , Fortney , J J , Gibson , N P , Goyal , J M , Helling , C , Mayne , N J & Mikal-Evans , T 2021 , ' Transmission spectroscopy with VLT FORS2 : a featureless spectrum for the low-density transiting exoplanet WASP-88b ' , Monthly Notices of the Royal Astronomical Society , vol. 506 , no. 2 , pp. 2853-2870 . https://doi.org/10.1093/mnras/stab1847
Publication
Monthly Notices of the Royal Astronomical Society
Status
Peer reviewed
ISSN
0035-8711Type
Journal article
Description
PS was supported by a UK Science and Technology Facilities Council (STFC) studentship. CH acknowledges funding from the European Union H2020-MSCA-ITN2019 under grant agreement no. 860470 (CHAMELEON). NM acknowledges funding from the UKRI Future Leaders Scheme (MR/T040866/1), Science and Technology Facilities Council Consolidated Grant (ST/R000395/1), and Leverhulme Trust research project grant (RPG-2020-82).Collections
Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.