ON THE SURVIVAL OF BROWN DWARFS AND PLANETS ENGULFED BY THEIR GIANT HOST STAR

Abstract

The recent discovery of two Earth-mass planets in close orbits around an\nevolved star has raised questions as to whether substellar companions can\nsurvive encounters with their host stars. We consider whether these companions\ncould have been stripped of significant amounts of mass during the phase when\nthey orbited through the dense inner envelopes of the giant. We apply the\ncriterion derived by Murray et al. for disruption of gravitationally bound\nobjects by ram pressure, to determine whether mass loss may have played a role\nin the histories of these and other recently discovered low-mass companions to\nevolved stars. We find that the brown dwarf and Jovian mass objects circling WD\n0137-349, SDSS J08205+0008, and HIP 13044 are most unlikely to have lost\nsignificant mass during the common envelope phase. However, the Earth-mass\nplanets found around KIC 05807616 could well be the remnant of one or two\nJovian mass planets that lost extensive mass during the common envelope phase.\n