An Earth-sized Planet on the Verge of Tidal Disruption

TOI-6255~b (GJ 4256) is an Earth-sized planet (1.079\pm0.065 R_\oplus) with an orbital period of only 5.7 hours. With the newly commissioned Keck Planet Finder (KPF) and CARMENES spectrographs, we determined the planet's mass to be 1.44\pm0.14 M_{\oplus}. The planet is just outside the Roche limit, with P_{\rm orb}/P_{\rm Roche} =... Show more