Probing the temperature gradient in the core boundary layer of stars with gravito-inertial modes: The case of KIC 7760680
| Autor: | Dominic M. Bowman, Mathias Michielsen, Conny Aerts |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
oscillations [stars]
Astronomy statistical [methods] FOS: Physical sciences Astrophysics asteroseismology Astronomy & Astrophysics stars: interiors 01 natural sciences Computer Science::Digital Libraries COOL STARS photometric [techniques] Methods: Statistical techniques: photometric 0103 physical sciences Radiative transfer Astrophysics::Solar and Stellar Astrophysics Stellar structure stars: oscillations (including pulsations) MASSES 010303 astronomy & astrophysics Mixing (physics) Solar and Stellar Astrophysics (astro-ph.SR) convection Physics interiors [stars] Science & Technology 010308 nuclear & particles physics ANGULAR-MOMENTUM TRANSPORT Astrophysics::Instrumentation and Methods for Astrophysics Asteroseismology Astronomy and Astrophysics Observable AGES Physics::History of Physics EVOLUTION Temperature gradient Stars Boundary layer Photometry (astronomy) Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science CONVECTION Physical Sciences Astrophysics::Earth and Planetary Astrophysics |
| Zdroj: | Astronomy & Astrophysics, 650, 1-20 Astronomy & Astrophysics, 650, pp. 1-20 |
| ISSN: | 0004-6361 |
| DOI: | 10.1051/0004-6361/202039926 |
| Popis: | Aims: We investigate the thermal and chemical structure in the near-core region of stars with a convective core by means of gravito-inertial modes. We do so by determining the probing power of different asteroseismic observables and fitting methodologies. We focus on the case of the B-type star KIC$\,$7760680, rotating at a quarter of its critical rotation velocity. Methods: We compute grids of 1D stellar structure and evolution models for two different prescriptions of the temperature gradient and mixing profile in the near-core region. We determine which of these prescriptions is preferred according to the prograde dipole modes detected in 4-yr $\textit{Kepler}$ photometry of KIC$\,$7760680. We consider different sets of asteroseismic observables and compare the outcomes of the regression problem for a $\chi^2$ and Mahalanobis Distance merit function, where the latter takes into account realistic uncertainties for the theoretical predictions and the former does not. Results: Period spacings of modes with consecutive radial order offer a better diagnostic than mode periods or mode frequencies for asteroseismic modelling of stars revealing only high-order gravito-inertial modes. We find KIC$\,$7760680 to reveal a radiative temperature gradient in models with convective boundary mixing, but less complex models without such mixing are statistically preferred for this rotating star, revealing extremely low vertical envelope mixing. Conclusions: Our results strongly suggest the use of measured individual period spacing values for modes of consecutive radial order as an asteroseismic diagnostic for stellar modelling of B-type pulsators with gravito-inertial modes. Comment: Accepted for publication in A&A, 20 pages, 30 figures, 11 tables |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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