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Title: Evolutionary Origins of Binary Neutron Star Mergers: Effects of Common Envelope Efficiency and Metallicity
Abstract The formation histories of compact binary mergers, especially stellar-mass binary black hole mergers, have recently come under increased scrutiny and revision. We revisit the question of the dominant formation channel and efficiency of forming binary neutron star (BNS) mergers. We use the stellar and binary evolution codeMESAand implement a detailed method for common envelope and mass transfer. We perform simulations for donor masses between 7 M⊙and 20 M⊙with a neutron star (NS) companion of 1.4 M⊙and 2.0 M⊙ at two metallicities, using varying common envelope efficiencies and two different prescriptions to determine if the donor undergoes core collapse or electron capture, given their helium and carbon–oxygen cores. In contrast to the case of binary black hole mergers, for an NS companion of 1.4 M⊙, all BNS mergers are formed following a common envelope phase. For an NS mass of 2.0 M⊙, we identify a small subset of mergers following only stable mass transfer if the NS receives a natal kick sampled from a Maxwellian distribution with velocity dispersionσ= 265 km s−1. Regardless of the supernova prescription, we find more BNS mergers at subsolar metallicity compared to solar.  more » « less
Award ID(s):
2207945
PAR ID:
10522314
Author(s) / Creator(s):
; ;
Publisher / Repository:
The Astrophysical Journal
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
955
Issue:
2
ISSN:
0004-637X
Page Range / eLocation ID:
133
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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