On the survival of brown dwarfs and planets engulfed by their giant host star

TL;DR

This paper investigates whether brown dwarfs and planets can survive engulfment by giant stars, finding that most are unlikely to lose significant mass, but some Earth-mass planets may be remnants of larger planets that lost mass.

Contribution

It applies a disruption criterion to assess mass loss of substellar companions during stellar evolution phases, providing insights into their survival and evolution.

Findings

Most brown dwarfs and Jovian planets likely survive common envelope phases.

Earth-mass planets around KIC 05807616 may be remnants of larger planets.

Mass loss during stellar engulfment can explain some observed low-mass companions.

Abstract

The recent discovery of two Earth-mass planets in close orbits around an evolved star has raised questions as to whether substellar companions can survive encounters with their host stars. We consider whether these companions could have been stripped of significant amounts of mass during the phase when they orbited through the dense inner envelopes of the giant. We apply the criterion derived by Murray et al. for disruption of gravitationally bound objects by ram pressure, to determine whether mass loss may have played a role in the histories of these and other recently discovered low-mass companions to evolved stars. We find that the brown dwarf and Jovian mass objects circling WD 0137-349, SDSS J08205+0008, and HIP 13044 are most unlikely to have lost significant mass during the common envelope phase. However, the Earth-mass planets found around KIC 05807616 could well be the remnant of one or two Jovian mass planets that lost extensive mass during the common envelope phase.