Numerical-relativity simulation for tidal disruption of white dwarfs by a supermassive black hole

Abstract

We study tidal disruption of white dwarfs in elliptic orbits with the eccenticity of $\sim 1/3$--$2/3$ by a non-spinning supermassive black hole of mass $M_{\rm BH}=10^5M_\odot$ in fully general relativistic simulations targeting the extreme mass-ratio inspiral leading eventually to tidal disruption. Numerical-relativity simulations are performed by employing a suitable formulation in which the weak self-gravity of white dwarfs is accurately solved. We reconfirm that tidal disruption occurs for white dwarfs of the typical mass of $\sim 0.6M_\odot$ and radius $\approx 1.2 \times 10^4$\,km near the marginally bound orbit around a non-spinning black hole with $M_{\rm BH}\alt 4\times 10^5M_\odot$.