학술논문
A close-in giant planet escapes engulfment by its star
Document Type
Working Paper
Author
Hon, Marc; Huber, Daniel; Rui, Nicholas Z.; Fuller, Jim; Veras, Dimitri; Kuszlewicz, James S.; Kochukhov, Oleg; Stokholm, Amalie; Rørsted, Jakob Lysgaard; Yıldız, Mutlu; Orhan, Zeynep Çelik; Örtel, Sibel; Jiang, Chen; Hey, Daniel R.; Isaacson, Howard; Zhang, Jingwen; Vrard, Mathieu; Stassun, Keivan G.; Shappee, Benjamin J.; Tayar, Jamie; Claytor, Zachary R.; Beard, Corey; Bedding, Timothy R.; Brinkman, Casey; Campante, Tiago L.; Chaplin, William J.; Chontos, Ashley; Giacalone, Steven; Holcomb, Rae; Howard, Andrew W.; Lubin, Jack; MacDougall, Mason; Montet, Benjamin T.; Murphy, Joseph M. A.; Ong, Joel; Pidhorodetska, Daria; Polansk, Alex S.; Rice, Malena; Stello, Dennis; Tyler, Dakotah; Van Zandt, Judah; Weiss, Lauren
Source
Subject
Language
Abstract
When main-sequence stars expand into red giants, they are expected to engulf close-in planets. Until now, the absence of planets with short orbital periods around post-expansion, core-helium-burning red giants has been interpreted as evidence that short-period planets around Sun-like stars do not survive the giant expansion phase of their host stars. Here we present the discovery that the giant planet 8 Ursae Minoris b orbits a core-helium-burning red giant. At a distance of only 0.5 au from its host star, the planet would have been engulfed by its host star, which is predicted by standard single-star evolution to have previously expanded to a radius of 0.7 au. Given the brief lifetime of helium-burning giants, the nearly circular orbit of the planet is challenging to reconcile with scenarios in which the planet survives by having a distant orbit initially. Instead, the planet may have avoided engulfment through a stellar merger that either altered the evolution of the host star or produced 8 Ursae Minoris b as a second-generation planet. This system shows that core-helium-burning red giants can harbour close planets and provides evidence for the role of non-canonical stellar evolution in the extended survival of late-stage exoplanetary systems.
Comment: Published in Nature on 28 June 2023. In press
Comment: Published in Nature on 28 June 2023. In press