# A possibly inflated planet around the bright, young star DS Tuc A

## TL;DR

This paper reports the validation of a young, possibly inflated giant planet around the bright star DS Tuc A, using TESS data, radial velocities, and adaptive optics, highlighting its potential for further characterization.

## Contribution

It confirms a young giant planet around DS Tuc A and provides detailed parameters, demonstrating the planet's suitability for future mass, atmospheric, and dynamical studies.

## Key findings

- Confirmed a young giant planet with R = 0.50 R_Jup around DS Tuc A.
- Placed an upper limit of 0.1 M_Jup on the planet's mass.
- Ruled out external companions beyond 40 au with adaptive optics.

## Abstract

The origin of the observed diversity of planetary system architectures is one of the main topic of the exoplanetary research. The detection of a statistically significant sample of planets around young stars allows us to study the early stages of planet formation and evolution, but only a handful of them is known so far. In this regard, a considerable contribution is expected from the NASA TESS satellite, which is now performing a survey of $\sim 85 \%$ of the sky to search for short-period transiting planets In its first month of operations, TESS found a planet candidate with an orbital period of 8.14 days around a member of the Tuc-Hor young association ($\sim$ 40 Myr), the G6V main component of the binary system DS\,Tuc. If confirmed, it would be the first transiting planet around a young star suitable for radial velocity and/or atmospheric characterization. We aim to validate the planetary nature of this companion and to measure its orbital and physical parameters. We obtain accurate planet parameters by coupling an independent reprocessing of the TESS light curve with improved stellar parameters and the dilution caused by the binary companion; we analyse high precision archival radial velocities to impose an upper limit of about 0.1 M$_{\rm Jup}$ on the planet mass; we finally rule out the presence of external companions beyond 40 au with adaptive optics images. We confirm the presence of a young, giant (${\rm R} = 0.50$ R$_{\rm Jup}$) planet having a not negligible possibility to be inflated (theoretical mass $\lesssim 20$ M$_{\oplus}$) around DS\,Tuc~A. We discuss the feasibility of mass determination, Rossiter-McLaughlin analysis and atmosphere characterization, allowed by the brightness of the star.