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

TL;DR

This paper presents fully general relativistic simulations of white dwarf tidal disruption by a supermassive black hole, confirming disruption occurs for typical white dwarf parameters near certain black hole mass thresholds.

Contribution

It introduces a numerical relativity approach to simulate white dwarf tidal disruption in extreme mass-ratio inspirals, accurately accounting for weak self-gravity effects.

Findings

Tidal disruption occurs for white dwarfs of ~0.6 solar masses and radius ~1.2×10^4 km.

Disruption happens near the marginally bound orbit for black holes with mass less than ~4×10^5 solar masses.

Simulations confirm the conditions under which white dwarfs are tidally disrupted by supermassive black holes.

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 $M_{\rm BH}\alt 4\times 10^5M_\odot$.