A case for Case A: detailed look at binary black hole formation through stable mass transfer

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Briel, Max M., Fragos, Tassos, Gallegos-Garcia, Monica, Ray, Anarya, Zevin, Michael, Chattaraj, Abhishek, Andrews, Jeff J., Kalogera, Vicky, Gossage, Seth, Srivastava, Philipp M., Teng, Elizabeth
Format: Preprint
Published: 2026
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866911687041351680
author Briel, Max M.
Fragos, Tassos
Gallegos-Garcia, Monica
Ray, Anarya
Zevin, Michael
Chattaraj, Abhishek
Andrews, Jeff J.
Kalogera, Vicky
Gossage, Seth
Srivastava, Philipp M.
Teng, Elizabeth
author_facet Briel, Max M.
Fragos, Tassos
Gallegos-Garcia, Monica
Ray, Anarya
Zevin, Michael
Chattaraj, Abhishek
Andrews, Jeff J.
Kalogera, Vicky
Gossage, Seth
Srivastava, Philipp M.
Teng, Elizabeth
contents In isolated binary evolution, binary black hole (BBH) mergers are generally formed through stable mass transfer (SMT) or common envelope evolution. In recent years, the SMT channel has received significant attention due to detailed binary models showing increased mass transfer stability compared to previous studies. In this work, we perform a full zero-age-main-sequence to compact object merger analysis using detailed binary models at eight metallicities between $10^{-4}Z_\odot$ and $2Z_\odot$ to self-consistently model the population properties of BBH mergers in the SMT channel, determined their progenitor initial conditional, and investigate the binary physics governing their formation and metallicity dependence. We use the population synthesis code POSYDON to determine the population of BBH mergers from SMT. Using its extended grids of MESA binary models, we determine the essential physics in the formation of BBH mergers. SMT produces BBH mergers predominantly from systems with $P_{ZAMS}\leq10$ days. In these systems, both the initial mass transfer between two stars and the subsequent interaction between the remaining star and the first-born BH take place while the respective donor star is on the main-sequence (Case A). We find a limited contribution from wider Case B/C systems. Without a natal kick, the SMT channel does not produce BBH mergers above $Z>0.2Z_\odot$ due to orbital widening from stellar wind mass loss. The primary BH mass distribution shows a strong dependence on metallicity, while the mass ratio prefers unity independent of metallicity due to mass ratio reversal. Additionally, the $χ_{eff}$ distributions contain peaks at $χ_{eff}=0$ and ~0.15 of which the former disappears at high metallicities. A mass-scaled natal kick leave this sub-population unchanged but introduce a low-mass, unequal mass ratio sub-population that merges due to their high eccentricity.
format Preprint
id arxiv_https___arxiv_org_abs_2602_03629
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A case for Case A: detailed look at binary black hole formation through stable mass transfer
Briel, Max M.
Fragos, Tassos
Gallegos-Garcia, Monica
Ray, Anarya
Zevin, Michael
Chattaraj, Abhishek
Andrews, Jeff J.
Kalogera, Vicky
Gossage, Seth
Srivastava, Philipp M.
Teng, Elizabeth
High Energy Astrophysical Phenomena
In isolated binary evolution, binary black hole (BBH) mergers are generally formed through stable mass transfer (SMT) or common envelope evolution. In recent years, the SMT channel has received significant attention due to detailed binary models showing increased mass transfer stability compared to previous studies. In this work, we perform a full zero-age-main-sequence to compact object merger analysis using detailed binary models at eight metallicities between $10^{-4}Z_\odot$ and $2Z_\odot$ to self-consistently model the population properties of BBH mergers in the SMT channel, determined their progenitor initial conditional, and investigate the binary physics governing their formation and metallicity dependence. We use the population synthesis code POSYDON to determine the population of BBH mergers from SMT. Using its extended grids of MESA binary models, we determine the essential physics in the formation of BBH mergers. SMT produces BBH mergers predominantly from systems with $P_{ZAMS}\leq10$ days. In these systems, both the initial mass transfer between two stars and the subsequent interaction between the remaining star and the first-born BH take place while the respective donor star is on the main-sequence (Case A). We find a limited contribution from wider Case B/C systems. Without a natal kick, the SMT channel does not produce BBH mergers above $Z>0.2Z_\odot$ due to orbital widening from stellar wind mass loss. The primary BH mass distribution shows a strong dependence on metallicity, while the mass ratio prefers unity independent of metallicity due to mass ratio reversal. Additionally, the $χ_{eff}$ distributions contain peaks at $χ_{eff}=0$ and ~0.15 of which the former disappears at high metallicities. A mass-scaled natal kick leave this sub-population unchanged but introduce a low-mass, unequal mass ratio sub-population that merges due to their high eccentricity.
title A case for Case A: detailed look at binary black hole formation through stable mass transfer
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2602.03629