A Cold and Superpuffy Planet on a Prograde Orbit
Loading...
Date
2026
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
We report the discovery of TOI-4507 b, a transiting sub-Saturn with a density <0.2 g cm−3 on a 105 days
prograde orbit around a 700 Myr old F star. The transits were detected using data from TESS as well as the
Antarctic telescope ASTEP. A joint analysis of the light curves and radial velocities from HARPS, FEROS, and
CORALIE confirmed the planetary nature of the signal, by limiting the mass to be below 20 M⊕ at 95%
confidence. The radial velocities also exhibit the Rossiter–McLaughlin effect and imply that the planet orbits the
star in a prograde orbit with a sky-projected obliquity
15 44
50 = + ° (|λ| < 80° at 3σ). With these characteristics,
TOI-4507 is one of the longest-period systems for which the stellar obliquity has been measured, and the planet is
among the longest-period and youngest “superpuff” planets yet discovered.