Fermionic Dark Matter and Electron-Capture Supernovae: Pathways to Low-Mass Neutron Stars

by Vishal Parmar (Istituto Nazionale di Fisica Nucleare)

Wednesday 19 Nov 2025, 14:30 → 15:30 Europe/Rome

Sala G. Galilei (131) (INFN - Pisa)

Abstract: 

Electron capture supernovae are emerging as a powerful channel for forming low mass neutron stars, supported by decades of theory and strengthened by recent observations such as SN 2018zd. In this talk I explore how fermionic asymmetric dark matter reshapes this evolutionary pathway. Using a general relativistic two fluid framework, in which ordinary matter and asymmetric dark matter evolve as gravity coupled but separately conserved fluids, we follow the collapse of neon rich white dwarfs that typically serve as progenitor cores. By conserving both baryon number and dark matter particle number during collapse, we establish a consistent mapping between the progenitor configuration and the final neutron star. The presence of asymmetric dark matter raises the central density of the white dwarf, lowers the gravitational mass required to trigger electron capture, and therefore enables electron capture supernovae from progenitors that would otherwise avoid collapse. The resulting remnants are stable dark matter admixed neutron stars with gravitational masses that can fall below current observational limits. We also find that the conversion energy during the transition from a white dwarf to a neutron star decreases significantly for heavier or more abundant dark matter, suggesting that unusually faint electron capture supernovae may serve as observable signatures of dark matter participation in stellar collapse.