Evolution and formation of ultramassive white dwarf stars: The case for a 9Msun progenitor

Fuente: arXiv
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Auteurs principaux: Antonini, Ana S. R., Romero, Alejandra D., Kepler, S. O.
Format: Preprint
Publié: 2026
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author Antonini, Ana S. R.
Romero, Alejandra D.
Kepler, S. O.
author_facet Antonini, Ana S. R.
Romero, Alejandra D.
Kepler, S. O.
contents We study the full evolution of a 1.313 Msun white dwarf star that descended from a 9 Msun main-sequence progenitor with an initial metallicity of Z=0.02. Using MESA r24.08.01, we calculate its entire evolution from pre-ZAMS to the WD cooling curve, including both the evolution through 139 thermal pulses and the post-AGB phase. The resulting remnant is an ultramassive H-deficient WD, for which the composition, in mass fraction, is 47.7% O16, 39.7% Ne20, 4.2% Mg24, 3.3% Na23 and 0.386% C12 -- corresponding to a total mass of 5 x 10^-3 Msun of C --, surrounded by a 1.5 x 10^-5 Msun He layer. We also investigate the effects of fully suppressing the TP-SAGB stage by adopting a high mass-loss rate only after the second dredge-up, and find only minor differences in the final mass and composition. In addition, we calculate models with and without phase separation during the WD stage, estimating a cooling delay of only 16 Myr. This is the first ultramassive white dwarf sequence for which both the TP-SAGB and post-AGB stages are calculated and, to our knowledge, the most massive WD model from complete evolution for which cooling times and detailed abundance profiles are published
format Preprint
id arxiv_https___arxiv_org_abs_2603_08573
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Evolution and formation of ultramassive white dwarf stars: The case for a 9Msun progenitor
Antonini, Ana S. R.
Romero, Alejandra D.
Kepler, S. O.
Solar and Stellar Astrophysics
We study the full evolution of a 1.313 Msun white dwarf star that descended from a 9 Msun main-sequence progenitor with an initial metallicity of Z=0.02. Using MESA r24.08.01, we calculate its entire evolution from pre-ZAMS to the WD cooling curve, including both the evolution through 139 thermal pulses and the post-AGB phase. The resulting remnant is an ultramassive H-deficient WD, for which the composition, in mass fraction, is 47.7% O16, 39.7% Ne20, 4.2% Mg24, 3.3% Na23 and 0.386% C12 -- corresponding to a total mass of 5 x 10^-3 Msun of C --, surrounded by a 1.5 x 10^-5 Msun He layer. We also investigate the effects of fully suppressing the TP-SAGB stage by adopting a high mass-loss rate only after the second dredge-up, and find only minor differences in the final mass and composition. In addition, we calculate models with and without phase separation during the WD stage, estimating a cooling delay of only 16 Myr. This is the first ultramassive white dwarf sequence for which both the TP-SAGB and post-AGB stages are calculated and, to our knowledge, the most massive WD model from complete evolution for which cooling times and detailed abundance profiles are published
title Evolution and formation of ultramassive white dwarf stars: The case for a 9Msun progenitor
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2603.08573