Asteroseismic Stellar Modelling: Systematics from the Treatment of the Initial Helium Abundance
| Autor: | Miguel T. Clara, Benard Nsamba, Nuno Moedas |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Physics
010308 nuclear & particles physics chemistry.chemical_element Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Radius Effective temperature 01 natural sciences Stars chemistry Big Bang nucleosynthesis Abundance (ecology) Ionization 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics Helium |
| Zdroj: | Astrophysics and Space Science Proceedings ISBN: 9783030553357 |
| DOI: | 10.1007/978-3-030-55336-4_34 |
| Popis: | Despite the fact that the initial helium abundance is an essential ingredient in modelling solar-type stars, its abundance in these stars remains a poorly constrained observational property. This is because the effective temperature in these stars is not high enough to allow helium ionization, not allowing any conclusions on its abundance when spectroscopic techniques are employed. To this end, stellar modellers resort to estimating the initial helium abundance via a semi-empirical helium-to-heavy element ratio, anchored to the standard Big Bang nucleosynthesis value. Depending on the choice of solar composition used in stellar model computations, the helium-to-heavy element ratio, (ΔY∕ ΔZ) is found to vary between 1 and 3. In this study, we use the Kepler LEGACY stellar sample, for which precise seismic data is available, and explore the systematic uncertainties on the inferred stellar parameters (radius, mass, and age) arising from adopting different values of ΔY∕ ΔZ, specifically, 1.4 and 2.0. The stellar grid constructed with a higher ΔY∕ ΔZ value yields lower radius and mass estimates. We found systematic uncertainties of 1.1%, 2.6%, and 13.1% on radius, mass, and ages, respectively. |
| Databáze: | OpenAIRE |
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