Binary Progenitors of Electron-capture Supernovae
Abstract
Electron-capture supernovae (ECSNe) arise from a narrow progenitor parameter space between oxygen-neon white dwarf formation and iron-core collapse supernovae, governed by the competition between core growth and envelope removal. Binary interactions modify this balance through mass transfer and mergers. Using the binary population synthesis framework POSYDON, we model ECSN progenitors across metallicities from Z/Z⊙=2 to 10−4, focusing on the initial parameter space, pre-supernova stripping, envelope-based classification, surviving companions, post-supernova orbits, and cosmic event rates. The lower edge of the binary ECSN initial primary mass lies near 7 M⊙, owing to efficient convective overshooting in the POSYDON grids, whereas the upper edge increases with metallicity because stronger line-driven winds require larger initial masses to build carbon-oxygen cores within the ECSN range. Stable mass transfer and mergers occupy distinct regions in initial mass ratio and orbital period space. ECSNe in bound binaries are divided into hydrogen-rich Type II (∼30%), IIb (∼10%), and Ib (∼60%) outcomes according to residual hydrogen and helium envelopes. Across all channels, approximately one-third of ECSNe have a bound companion at explosion; the remaining two-thirds do not. Among these bound systems, approximately 90% of the companions are main-sequence stars at explosion. These companions exhibit a bimodal spin distribution, including a rapidly rotating component associated with prior mass transfer. Evolved-star and compact-object companions each account for only a few percent. Combining the formation efficiencies with cosmic star formation and metallicity evolution models yields an intrinsic ECSN rate peaking at z∼2−3 and declining at higher redshifts. Over cosmic history, ECSNe contribute approximately 1%−4% of all core-collapse supernovae.
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BibTeX
@misc{zhong2026binary,
title = {{Binary Progenitors of Electron-capture Supernovae}},
author = {Liji Zhong and Yong Shao},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.34699},
eprint = {2610.34699},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.34699},
}
RIS
TY - UNPB
TI - Binary Progenitors of Electron-capture Supernovae
AU - Liji Zhong
AU - Yong Shao
PY - 2026
DA - 2026/10/26
PB - arXiv
DO - 10.48550/arxiv.2610.34699
UR - https://arxiv.org/abs/2610.34699
AB - Electron-capture supernovae (ECSNe) arise from a narrow progenitor parameter space between oxygen-neon white dwarf formation and iron-core collapse supernovae, governed by the competition between core growth and envelope removal. Binary interactions modify this balance through mass transfer and mergers. Using the binary population synthesis framework POSYDON, we model ECSN progenitors across metallicities from Z/Z_⊙=2 to 10^−4, focusing on the initial parameter space, pre-supernova stripping, envelope-based classification, surviving companions, post-supernova orbits, and cosmic event rates. The lower edge of the binary ECSN initial primary mass lies near 7 M_⊙, owing to efficient convective overshooting in the POSYDON grids, whereas the upper edge increases with metallicity because stronger line-driven winds require larger initial masses to build carbon-oxygen cores within the ECSN range. Stable mass transfer and mergers occupy distinct regions in initial mass ratio and orbital period space. ECSNe in bound binaries are divided into hydrogen-rich Type II (∼30%), IIb (∼10%), and Ib (∼60%) outcomes according to residual hydrogen and helium envelopes. Across all channels, approximately one-third of ECSNe have a bound companion at explosion; the remaining two-thirds do not. Among these bound systems, approximately 90% of the companions are main-sequence stars at explosion. These companions exhibit a bimodal spin distribution, including a rapidly rotating component associated with prior mass transfer. Evolved-star and compact-object companions each account for only a few percent. Combining the formation efficiencies with cosmic star formation and metallicity evolution models yields an intrinsic ECSN rate peaking at z∼2−3 and declining at higher redshifts. Over cosmic history, ECSNe contribute approximately 1%−4% of all core-collapse supernovae.
ER -