Carbon-Reaction Constraints on Stellar Evolution: White-Dwarf Heating, Carbon-Burning Products, and Black-Hole Masses
Abstract
The effects of 12C+12C fusion and 12C(α,γ)16O capture on stellar heating, composition, and black-hole masses are examined. Rates from a published Bayesian analysis of carbon fusion are used in calculations with MESA. In an accreting carbon--oxygen white dwarf, the Bayesian rates move the point at which nuclear heating equals combined neutrino and surface photon losses to slightly larger stellar masses and higher central temperatures and densities. At an accretion rate of 10−7 M⊙ yr−1, the Bayesian median gives a central temperature approximately 2.57% higher and a central density 18.9% higher than the calculation using the standard CF88 rate. A separate calculation follows carbon burning in an initially 20 M⊙, Z=0.0142 star. Relative to the CF88 rate with MESA's standard division between proton and alpha channels, the Bayesian-median rate with the proton-to-alpha ratio of Yang et al. increases the neon-20 mass remaining at central carbon depletion by 10.8% and decreases the sodium-23 mass by 28.7%. For helium capture on carbon, the nuclear constraint Stot(300 keV)=118±17 keV b is applied to the published Z=10−5 stellar models of Farag et al. Linear interpolation gives a maximum black-hole mass below the pair-instability gap of approximately $61.5−−77.4\,M_\odot$ within the assumptions of those models. New MESA calculations at Z=0.00142 give smaller bound masses before collapse. Differences in the stellar assumptions prevent attributing the difference between the two curves to metallicity alone.
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BibTeX
@misc{mukhamedzhanov2026carbonreaction,
title = {{Carbon-Reaction Constraints on Stellar Evolution: White-Dwarf Heating, Carbon-Burning Products, and Black-Hole Masses}},
author = {Akram Mukhamedzhanov},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.04197},
eprint = {2611.04197},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.04197},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Carbon-Reaction Constraints on Stellar Evolution: White-Dwarf Heating, Carbon-Burning Products, and Black-Hole Masses
AU - Akram Mukhamedzhanov
PY - 2026
DA - 2026/11/03
PB - arXiv
DO - 10.48550/arxiv.2611.04197
UR - https://arxiv.org/abs/2611.04197
AB - The effects of ^12C+^12C fusion and ^12C(α,γ)^16O capture on stellar heating, composition, and black-hole masses are examined. Rates from a published Bayesian analysis of carbon fusion are used in calculations with MESA. In an accreting carbon--oxygen white dwarf, the Bayesian rates move the point at which nuclear heating equals combined neutrino and surface photon losses to slightly larger stellar masses and higher central temperatures and densities. At an accretion rate of 10^−7 M_⊙ yr^−1, the Bayesian median gives a central temperature approximately 2.57% higher and a central density 18.9% higher than the calculation using the standard CF88 rate. A separate calculation follows carbon burning in an initially 20 M_⊙, Z=0.0142 star. Relative to the CF88 rate with MESA's standard division between proton and alpha channels, the Bayesian-median rate with the proton-to-alpha ratio of Yang et al. increases the neon-20 mass remaining at central carbon depletion by 10.8% and decreases the sodium-23 mass by 28.7%. For helium capture on carbon, the nuclear constraint S_tot(300 keV)=118±17 keV b is applied to the published Z=10^−5 stellar models of Farag et al. Linear interpolation gives a maximum black-hole mass below the pair-instability gap of approximately $61.5−−77.4\,M_\odot$ within the assumptions of those models. New MESA calculations at Z=0.00142 give smaller bound masses before collapse. Differences in the stellar assumptions prevent attributing the difference between the two curves to metallicity alone.
ER -