Revisiting constraints on asymmetric dark matter from collapse in white dwarf stars

TL;DR

This paper explores how asymmetric dark matter influences white dwarf stars, revealing that dark matter collapse leads to black hole formation and detectable astrophysical signals, challenging previous supernova ignition models.

Contribution

It introduces a revised understanding of dark matter-induced collapse in white dwarfs, highlighting black hole formation and associated observable signals, contrasting with earlier supernova ignition theories.

Findings

Mini black holes form inside white dwarfs due to dark matter collapse.

Electromagnetic transients lasting about a second can be observed.

Gravitational wave signals from black hole mergers are detectable by LIGO/Virgo.

Abstract

The runaway collapse phase of a small dark matter cluster inside a white dwarf star encompasses a reversible stage, where heat can be transferred back and forth between nuclear and dark matter. Induced nuclear burning phases are stable and early carbon depletion undermines previous claims of type Ia supernova ignition. Instead, mini black holes are formed at the center of the star that either evaporate or accrete stellar material until a macroscopic sub-Chandrasekhar-mass black hole is formed. In the latter case, a 0.1 to 1 second lasting electromagnetic transient signal can be detected upon ejection of the white dwarf's potential magnetic field. Binary systems that transmute to black holes and subsequently merge emit gravitational waves. Advanced LIGO/Virgo should detect one such sub-Chandrasekhar binary black hole inspiral per year, while future Einstein telescope-like facilities will detect thousands per year. The effective spin parameter distribution is peaked at 0.2 and permits future studies to disentangle from primordial sub-Chandrasekhar black holes. Such signatures are compatible with current direct detection constraints, as well as with neutron star constraints in the case of bosonic dark matter, even though they remain in conflict with the fermionic case for part of the parameter space.