White Dwarfs as Dark Matter Detectors

TL;DR

This paper explores how dark matter interactions within white dwarfs can trigger supernovae, providing new constraints on ultra-heavy dark matter candidates and suggesting an alternative supernova ignition mechanism.

Contribution

It introduces new constraints on ultra-heavy dark matter particles that heat white dwarfs via standard model particles, expanding the understanding of dark matter's role in stellar explosions.

Findings

Constraints on ultra-heavy DM from white dwarf observations

Ruling out supersymmetric Q-ball DM in certain parameter spaces

Proposing an alternative supernova ignition mechanism

Abstract

Dark matter that is capable of sufficiently heating a local region in a white dwarf will trigger runaway fusion and ignite a type Ia supernova. This was originally proposed in Graham et al. (2015) and used to constrain primordial black holes which transit and heat a white dwarf via dynamical friction. In this paper, we consider dark matter (DM) candidates that heat through the production of high-energy standard model (SM) particles, and show that such particles will efficiently thermalize the white dwarf medium and ignite supernovae. Based on the existence of long-lived white dwarfs and the observed supernovae rate, we derive new constraints on ultra-heavy DM which produce SM particles through DM-DM annihilations, DM decays, and DM-SM scattering interactions in the stellar medium. As a concrete example, we rule out supersymmetric Q-ball DM in parameter space complementary to terrestrial bounds. We put further constraints on DM that is captured by white dwarfs, considering the formation and self-gravitational collapse of a DM core which heats the star via decays and annihilations within the core. It is also intriguing that the DM-induced ignition discussed in this work provide an alternative mechanism of triggering supernovae from sub-Chandrasekhar, non-binary progenitors.