Impact of Sub-MeV Dark Matter on the Cooling of Pulsating White Dwarfs

TL;DR

This study investigates how sub-MeV dark matter interacts with white dwarfs and concludes that such dark matter has a negligible effect on their cooling, based on observational data and numerical calculations.

Contribution

The paper provides a detailed numerical analysis of dark matter interactions within white dwarfs and assesses their impact on stellar cooling, a novel approach in this context.

Findings

Maximum dark matter cooling luminosity is about 10^22 erg/s.

Sub-MeV dark matter cannot significantly accelerate white dwarf cooling.

Potential future observations could probe dark matter properties in specific mass and cross-section ranges.

Abstract

In our galaxy, white dwarfs inevitably undergo scattering and capture processes with the interstellar diffuse dark matter. The captured dark matter forms a dark halo that eventually evaporates or annihilates. Theoretical pulsation modes and observations of pulsating white dwarfs provide predictions about their evolution. This motivates us to study the impact of sub-MeV interstellar dark matter on the cooling processes of white dwarfs. In this work, we consider the collisions between dark matter and relativistic degenerate electrons inside white dwarfs, numerically calculating the energy input and output results from scattering, capture, evaporation, and annihilation processes. Based on observational data from G117-B15, we conclude that the maximum cooling luminosity of the interstellar sub-MeV dark matter is approximately $10^{22} \, \text{erg}/\text{s}$, which is insufficient to provide an effective cooling mechanism for white dwarfs. Finally, if future observations detect a pulsating white dwarf in the Galactic center, the potential sensitivity of this scenario could extend to the region$10^{-3}\,\text{MeV} < m_\chi < 10 \, \text{MeV}$ and $6.02 \times 10^{-38}\,\text{cm}^2 > \sigma_0 \geq 1.5 \times 10^{40} \, \text{cm}^2$.