Quantifying Systematic Uncertainties in White Dwarf Cooling Age Determinations
Cooling ages of white dwarfs are routinely determined by mapping effective temperatures and masses to ages using evolutionary models. Typically, the reported uncertainties on cooling ages only consider the error propagation of the uncertainties on the spectroscopically or photometrically determined...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adc10f |
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| author | Praneet Pathak Simon Blouin Falk Herwig |
| author_facet | Praneet Pathak Simon Blouin Falk Herwig |
| author_sort | Praneet Pathak |
| collection | DOAJ |
| description | Cooling ages of white dwarfs are routinely determined by mapping effective temperatures and masses to ages using evolutionary models. Typically, the reported uncertainties on cooling ages only consider the error propagation of the uncertainties on the spectroscopically or photometrically determined T _eff and mass. However, cooling models are themselves uncertain, given their dependence on many poorly constrained inputs. This paper estimates these systematic model uncertainties. We use MESA to generate cooling sequences of 0.5–1.0 M _⊙ hydrogen-atmosphere white dwarfs with carbon–oxygen cores under different assumptions regarding the chemical stratification of their core, the thickness of their helium envelope, their hydrogen content, and the conductive opacities employed in the calculations. The parameter space explored is constrained by the range of values predicted by a variety of stellar evolution models and inferred from asteroseismological studies. For a 0.6 M _⊙ white dwarf, we find an uncertainty of 0.03 Gyr at 10,000 K (corresponding to a 5% relative uncertainty) and 0.8 Gyr at 4000 K (9%). This uncertainty is significant, as it is comparable to the age uncertainty obtained by propagating the measurement errors on T _eff and mass for a typical white dwarf. We also separately consider the potential impact of ^22 Ne shell distillation, which plausibly leads to an additional uncertainty of ∼1 Gyr for crystallized white dwarfs. We provide a table of our simulation results that can be used to evaluate the systematic model uncertainty based on a white dwarf’s T _eff and mass. We encourage its use in all future studies where white dwarf cooling ages are measured. |
| format | Article |
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| institution | DOAJ |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
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| spelling | doaj-art-b94a44a4b54d424fb2860bab2a55ecdf2025-08-20T03:18:50ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01983215810.3847/1538-4357/adc10fQuantifying Systematic Uncertainties in White Dwarf Cooling Age DeterminationsPraneet Pathak0https://orcid.org/0009-0005-9976-1882Simon Blouin1https://orcid.org/0000-0002-9632-1436Falk Herwig2https://orcid.org/0000-0001-8087-9278Department of Physics & Astronomy, University of Victoria , Victoria, BC, V8W 2Y2, CanadaDepartment of Physics & Astronomy, University of Victoria , Victoria, BC, V8W 2Y2, CanadaDepartment of Physics & Astronomy, University of Victoria , Victoria, BC, V8W 2Y2, CanadaCooling ages of white dwarfs are routinely determined by mapping effective temperatures and masses to ages using evolutionary models. Typically, the reported uncertainties on cooling ages only consider the error propagation of the uncertainties on the spectroscopically or photometrically determined T _eff and mass. However, cooling models are themselves uncertain, given their dependence on many poorly constrained inputs. This paper estimates these systematic model uncertainties. We use MESA to generate cooling sequences of 0.5–1.0 M _⊙ hydrogen-atmosphere white dwarfs with carbon–oxygen cores under different assumptions regarding the chemical stratification of their core, the thickness of their helium envelope, their hydrogen content, and the conductive opacities employed in the calculations. The parameter space explored is constrained by the range of values predicted by a variety of stellar evolution models and inferred from asteroseismological studies. For a 0.6 M _⊙ white dwarf, we find an uncertainty of 0.03 Gyr at 10,000 K (corresponding to a 5% relative uncertainty) and 0.8 Gyr at 4000 K (9%). This uncertainty is significant, as it is comparable to the age uncertainty obtained by propagating the measurement errors on T _eff and mass for a typical white dwarf. We also separately consider the potential impact of ^22 Ne shell distillation, which plausibly leads to an additional uncertainty of ∼1 Gyr for crystallized white dwarfs. We provide a table of our simulation results that can be used to evaluate the systematic model uncertainty based on a white dwarf’s T _eff and mass. We encourage its use in all future studies where white dwarf cooling ages are measured.https://doi.org/10.3847/1538-4357/adc10fStellar agesStellar evolutionUncertainty boundsWhite dwarf stars |
| spellingShingle | Praneet Pathak Simon Blouin Falk Herwig Quantifying Systematic Uncertainties in White Dwarf Cooling Age Determinations The Astrophysical Journal Stellar ages Stellar evolution Uncertainty bounds White dwarf stars |
| title | Quantifying Systematic Uncertainties in White Dwarf Cooling Age Determinations |
| title_full | Quantifying Systematic Uncertainties in White Dwarf Cooling Age Determinations |
| title_fullStr | Quantifying Systematic Uncertainties in White Dwarf Cooling Age Determinations |
| title_full_unstemmed | Quantifying Systematic Uncertainties in White Dwarf Cooling Age Determinations |
| title_short | Quantifying Systematic Uncertainties in White Dwarf Cooling Age Determinations |
| title_sort | quantifying systematic uncertainties in white dwarf cooling age determinations |
| topic | Stellar ages Stellar evolution Uncertainty bounds White dwarf stars |
| url | https://doi.org/10.3847/1538-4357/adc10f |
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