# Physical properties and transmission spectrum of the WASP-74 planetary system from multi-band photometry

## TL;DR

This study uses multi-band photometry and high-resolution spectroscopy to refine the physical parameters of the WASP-74b system and suggests the presence of TiO and VO gases in its atmosphere based on the transmission spectrum.

## Contribution

It provides improved measurements of the planet's and host star's properties and constructs a transmission spectrum indicating atmospheric composition.

## Key findings

- Smaller radius and mass for WASP-74b and its host star than previous estimates.
- Detection of strong optical absorbers, TiO and VO, in the planet's atmosphere.
- Transmission spectrum consistent with the presence of gaseous absorbers.

## Abstract

We present broad-band photometry of eleven planetary transits of the hot Jupiter WASP-74b, using three medium-class telescopes and employing the telescope-defocussing technique. Most of the transits were monitored through I filters and one was simultaneously observed in five optical (U, g', r', i', z') and three near infrared (J, H, K) passbands, for a total of 18 light curves. We also obtained new high-resolution spectra of the host star. We used these new data to review the orbital and physical properties of the WASP-74 planetary system. We were able to better constrain the main system characteristics, measuring smaller radius and mass for both the hot Jupiter and its host star than previously reported in the literature. Joining our optical data with those taken with the HST in the near infrared, we built up an observational transmission spectrum of the planet, which suggests the presence of strong optical absorbers, as TiO and VO gases, in its atmosphere.