J/MNRAS/548/G469 9Msun ultramassive WD stars progenitor (Antonini+, 2026)
Evolution and formation of ultramassive white dwarf stars:
The case for a 9Msun progenitor.
Antonini A.S.R., Romero A.D., Kepler S.O.
<Mon. Not. R. Astron. Soc. 548, G469 (2026)>
=2026MNRAS.548ag469A (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Spectral types ; Stars, early-type ;
Stars, late-type ; Stars, supergiant ; Stars, white dwarf ; Models
Keywords: stars: AGB and post-AGB - stellar evolution - white dwarf
Abstract:
We study the full evolution of a 1.313M☉ white dwarf star that
descended from a 9M☉ 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% 16O, 39.7% 20Ne, 4.2%
24Mg, 3.3% 23Na and 0.386% 12C -- corresponding to a total mass
of 5x10-3M☉ of C --, surrounded by a 1.5x10-5M☉ 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
16Myr. 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.
Description:
Set of 3 .dat files with the cooling tracks for the WD sequences
computed. Designations "baseline", "def" and "noPS" are the same
adopted in the paper.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
baseline.dat 182 33786 cooling data for our baseline model
nops.dat 182 4110 cooling data for our model calculated
without phase separation (noPS)
def.dat 182 5362 cooling data for our model calculated with the
default Skye regime for one-component plasma fits
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Byte-by-byte Description of file: baseline.dat nops.dat def.dat
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Bytes Format Units Label Explanations
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1- 18 F18.16 [K] logTeff Effective temperature in log scale
20- 41 F22.19 [Lsun] logL Luminosity in log scale
43- 59 F17.15 [cm/s2] logg Surface gravity in log scale
61- 79 F19.16 [Rsun] logR Radius in log scale
81-105 F25.14 yr tcool Cooling age
107-124 F18.15 [10-7J/cm3] logPc Central Pressure in log scale
126-142 F17.15 [g/cm3] logrhoc Central density in log scale
144-161 F18.16 [K] logTc Central Temperature in log scale
163-182 F20.15 --- Gammac Central coulomb interaction parameter
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Acknowledgements:
Ana Antonini Santa Rosa, ana.antonini(at)ufrgs.br
License: CC-BY-4.0 [see https://spdx.org/licenses/]
(End) Patricia Vannier [CDS] 06-Mar-2026