TESS Investigation -- Demographics of Young Exoplanets (TI-DYE) IV: a Jovian radius planet orbiting a 34 Myr Sun-like star in the Vela association

TL;DR

This paper reports the validation of a young Jovian-sized exoplanet orbiting a 34-million-year-old Sun-like star in the Vela association, contributing to understanding planet formation in early stellar ages.

Contribution

It confirms the existence of a young, Jovian-radius planet around a 34 Myr star and refines the age of the Vela cluster, expanding the sample of infant exoplanets.

Findings

TOI-6448 b is an 8.8 Re planet with a 14.8-day orbit.

The host star is confirmed to be 34 +/- 3 Myr old.

Young planets like TOI-6448 b are more common than previously thought.

Abstract

The discovery of infant (< 50 Myr), close-in (<30-day period) planets is vital in understanding the formation mechanisms that lead to the distribution of mature transiting planets as discovered by Kepler. Despite several discoveries in this age bin, the sample is still too small for a robust statistical comparison to older planets. Here we report the validation of TOI-6448 b, an 8.8 +/- 0.8 Re planet on a 14.8 day orbit. TOI-6448 was previously identified to be a likely member of Vela Population IV. We confirm the star's membership and re-derive the age of the cluster using isochrones, variability, and gyrochronology. We find the star, and thus planet, to be 34 +/- 3 Myr. Like other young planets, TOI-6448 b lands in a region of parameter space with few older planets. While just one data point, this fits with prior findings of an excess of 5-11Re planets around young stars far beyond what can be explained by reduced sensitivity at young ages. Our ongoing search of Vela, Taurus-Auriga, Sco-Cen, and Orion are expected to reveal dozens more < 50 Myr transiting planets.