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Carbon–Oxygen Phase Separation in Modules for Experiments in Stellar Astrophysics (MESA) White Dwarf Models
- Source :
- The Astrophysical Journal, Vol 950, Iss 2, p 115 (2023)
- Publication Year :
- 2023
- Publisher :
- IOP Publishing, 2023.
-
Abstract
- We enhance the treatment of crystallization for models of white dwarfs (WDs) in the stellar evolution software Modules for Experiments in Stellar Astrophysics (MESA) by implementing carbon–oxygen (C/O) phase separation. The phase separation process during crystallization leads to transport of oxygen toward the centers of WDs, resulting in a more compact structure that liberates gravitational energy as additional heating that modestly slows WD cooling timescales. We quantify this cooling delay in MESA C/O WD models over the mass range 0.5–1.0 M _⊙ , finding delays of 0.5–0.8 Gyr for typical C/O interior profiles. MESA WD cooling timescales including this effect are generally comparable to other WD evolution models that make similar assumptions about input physics. When considering phase separation alongside ^22 Ne sedimentation, however, we find that both MESA and BaSTI WD cooling models predict a more modest sedimentation delay than the latest LPCODE models, and this may therefore require a reevaluation of previously proposed solutions to some WD cooling anomalies that were based on LPCODE models of ^22 Ne sedimentation. Our implementation of C/O phase separation in the open-source stellar evolution software MESA provides an important tool for building realistic grids of WD cooling models, as well as a framework for expanding on our implementation to explore additional physical processes related to phase transitions and associated fluid motions in WD interiors.
- Subjects :
- Stellar physics
White dwarf stars
Astrophysics
QB460-466
Subjects
Details
- Language :
- English
- ISSN :
- 15384357
- Volume :
- 950
- Issue :
- 2
- Database :
- Directory of Open Access Journals
- Journal :
- The Astrophysical Journal
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.07f1b99d63ee425f9c372d86c61c5db6
- Document Type :
- article
- Full Text :
- https://doi.org/10.3847/1538-4357/acd057