Atypical Thermonuclear Supernovae from Tidally Crushed White Dwarfs

TL;DR

This paper proposes that white dwarfs tidally disrupted by intermediate mass black holes in globular clusters can trigger explosive nuclear burning, leading to a new class of thermonuclear supernovae with distinct observational signatures.

Contribution

It introduces a detailed model of white dwarf tidal disruption by IMBHs, demonstrating the potential for explosive ignition and proposing a new supernova mechanism.

Findings

White dwarf disruptions can trigger nuclear explosions.

Such supernovae are less frequent than Type Ia but detectable.

Modeling shows ignition is a natural outcome of close encounters.

Abstract

Suggestive evidence has accumulated that intermediate mass black holes (IMBH) exist in some globular clusters. As stars diffuse in the cluster, some will inevitable wander sufficiently close to the hole that they suffer tidal disruption. An attractive feature of the IMBH hypothesis is its potential to disrupt not only solar-type stars but also compact white dwarf stars. Attention is given to the fate of white dwarfs that approach the hole close enough to be disrupted and compressed to such extent that explosive nuclear burning may be triggered. Precise modeling of the dynamics of the encounter coupled with a nuclear network allow for a realistic determination of the explosive energy release, and it is argued that ignition is a natural outcome for white dwarfs of all varieties passing well within the tidal radius. Although event rates are estimated to be significantly less than the rate of normal Type Ia supernovae, such encounters may be frequent enough in globular clusters harboring an IMBH to warrant a search for this new class of supernova.