# Accretion-Induced Collapse of Dark Matter Admixed White Dwarfs -- I: Formation of Low-mass Neutron Stars

## TL;DR

This study uses hydrodynamics simulations to explore how dark matter in white dwarfs influences their collapse into low-mass neutron stars, providing a potential explanation for observed low-mass pulsars.

## Contribution

It demonstrates that dark matter admixture in white dwarfs can lead to the formation of low-mass neutron stars, a novel formation pathway not accounted for in traditional models.

## Key findings

- Dark matter presence slows collapse and reduces neutron star mass.
- Low-mass neutron stars (~1.0 M_sun) can form via this accretion-induced collapse.
- Potential explanation for observed low-mass pulsars like J0453+1559.

## Abstract

Recently observed pulsars with masses $\sim 1.1 ~M_{\odot}$ challenge the conventional neutron star (NS) formation path by core-collapse supernova (CCSN). Using spherically symmetric hydrodynamics simulations, we follow the collapse of a massive white dwarf (WD) core triggered by electron capture, until the formation of a proto-NS (PNS). For initial WD models with the same central density, we study the effects of a static, compact dark matter (DM) admixed core on the collapse and bounce dynamics and mass of the PNS, with DM mass $\sim 0.01 ~M_{\odot}$. We show that increasing the admixed DM mass generally leads to slower collapse and smaller PNS mass, down to about 1.0 $M_{\odot}$. Our results suggest that the accretion-induced collapse of dark matter admixed white dwarfs can produce low-mass neutron stars, such as the observed low-mass pulsar J0453+1559, which cannot be obtained by conventional NS formation path by CCSN.