Transmission spectroscopy with VLT FORS2: a featureless spectrum for the low-density transiting exoplanet WASP-88b
- Spyratos, Petros;
- Nikolov, Nikolay;
- Southworth, John;
- Constantinou, Savvas;
- Madhusudhan, Nikku;
- Carter, Aarynn L;
- de Mooij, Ernst JW;
- Fortney, Jonathan J;
- Gibson, Neale P;
- Goyal, Jayesh M;
- Helling, Christiane;
- Mayne, Nathan J;
- Mikal-Evans, Thomas
Abstract
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.
Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.