Mass Ejection Driven by Sudden Energy Deposition in Stellar Envelopes

Abstract

A number of stellar astrophysical phenomena, such as tidal novae and planetary engulfment, involve sudden injection of sub-binding energy in a thin layer within the star, leading to mass ejection of the stellar envelope. We use a 1D hydrodynamical model to survey the stellar response and mass loss for various amounts ($E_{\mathrm{dep}}$) and locations of the energy deposition. We find that the total mass ejection has a nontrivial dependence on $E_{\mathrm{dep}}$ due to the varying strengths of mass ejection events, which are associated with density/pressure waves breaking out from the stellar surface. The rapid occurrence of multiple breakouts may present a unique observational signature for sudden envelope heating events in stars.