The Hubble PanCET program: Transit and Eclipse Spectroscopy of the Hot Jupiter WASP-74b

TL;DR

This paper presents comprehensive Hubble and Spitzer transit and eclipse spectra of the hot Jupiter WASP-74b, revealing a muted water feature, Rayleigh scattering, and a blackbody-like spectrum, contributing valuable data to exoplanet atmospheric studies.

Contribution

It provides the most complete and precise atmospheric spectra of WASP-74b, adding new observational data and challenging previous reports of TiO/VO and super-Rayleigh scattering.

Findings

No evidence for TiO/VO or super-Rayleigh scattering.

Muted water feature with strong Rayleigh scattering.

Featureless blackbody-like spectrum in eclipse.

Abstract

Planets are like children with each one being unique and special. A better understanding of their collective properties requires a deeper understanding of each planet. Here we add the transit and eclipse spectra of hot Jupiter WASP-74b into the ever growing dataset of exoplanet atmosphere spectral library. With six transits and three eclipses using the Hubble Space Telescope (HST) and Spitzer Space Telescope (\textit{Spitzer}), we present the most complete and precise atmospheric spectra of WASP-74b. We found no evidence for TiO/VO nor super-Rayleigh scattering reported in previous studies. The transit shows a muted water feature with strong Rayleigh scattering extending into the infrared. The eclipse shows a featureless blackbody-like WFC3/G141 spectrum and a weak methane absorption feature in the Spitzer 3.6 $\mu m$ band. Future James Webb Space Telescope (JWST) follow up observations are needed to confirm these results.