Accretion-induced Collapse of Dark Matter Admixed White Dwarfs. I. Formation of Low-mass Neutron Stars

Abstract

Abstract Recently observed pulsars with masses ∼1.1 M ⊙ 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 ∼0.01 M ⊙. We show that increasing the admixed DM mass generally leads to a slower collapse and smaller PNS mass, down to about 1.0 M ⊙. Our results suggest that the accretion-induced collapse of DM admixed WDs can produce low-mass NSs, such as the observed low-mass pulsar J0453+1559, which cannot be obtained by conventional NS formation path by CCSN.