Characterisation of FG-type stars with an improved transport of chemical elements
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arXiv
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| Main Authors: | , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866929225258237952 |
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| author | Moedas, Nuno Bossini, Diego Deal, Morgan Cunha, Margarida |
| author_facet | Moedas, Nuno Bossini, Diego Deal, Morgan Cunha, Margarida |
| contents | Context. The modelling of chemical transport mechanisms is crucial for accurate stellar characterizations. Atomic diffusion is one of these processes and it is commonly included in stellar models. However, it is usually neglected for F-type or more massive stars because it produces surface abundance variations that are unrealistic. Additional mechanisms to counteract atomic diffusion must therefore be considered. It has been demonstrated that turbulent mixing can prevent the surface abundance over-variations, and can also be calibrated to mimic the effects of radiative accelerations on iron. Aims. We aim to evaluate the effect of a calibrated turbulent mixing on the characterisation of a sample of F-type stars, and how the estimates compare with those obtained when the chemical transport mechanisms are neglected. Methods. We selected stars from two samples - one from the Kepler LEGACY sample and the other from a sample of Kepler planet-hosting stars. We inferred their stellar properties using two grids. The first grid considers atomic diffusion only in models that do not show chemical over-variations at the stellar surface. The second grid includes atomic diffusion in all the stellar models and the calibrated turbulent mixing to avoid unrealistic surface abundances. Results. Comparing the derived results from the two grids, we found that the results for the more massive stars in our sample will have higher dispersion in the inferred values of mass, radius and age, due to the absence of atomic diffusion in one of the grids. This can lead to relative uncertainties for individual stars of up to 5% for masses, 2% for radii and 20% for ages. Conclusions. This work shows that a proper modelling of the microscopic transport processes is key for an accurate estimation of their fundamental properties not only for G-type stars, but also for F-type stars. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2401_14924 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Characterisation of FG-type stars with an improved transport of chemical elements Moedas, Nuno Bossini, Diego Deal, Morgan Cunha, Margarida Solar and Stellar Astrophysics Earth and Planetary Astrophysics Context. The modelling of chemical transport mechanisms is crucial for accurate stellar characterizations. Atomic diffusion is one of these processes and it is commonly included in stellar models. However, it is usually neglected for F-type or more massive stars because it produces surface abundance variations that are unrealistic. Additional mechanisms to counteract atomic diffusion must therefore be considered. It has been demonstrated that turbulent mixing can prevent the surface abundance over-variations, and can also be calibrated to mimic the effects of radiative accelerations on iron. Aims. We aim to evaluate the effect of a calibrated turbulent mixing on the characterisation of a sample of F-type stars, and how the estimates compare with those obtained when the chemical transport mechanisms are neglected. Methods. We selected stars from two samples - one from the Kepler LEGACY sample and the other from a sample of Kepler planet-hosting stars. We inferred their stellar properties using two grids. The first grid considers atomic diffusion only in models that do not show chemical over-variations at the stellar surface. The second grid includes atomic diffusion in all the stellar models and the calibrated turbulent mixing to avoid unrealistic surface abundances. Results. Comparing the derived results from the two grids, we found that the results for the more massive stars in our sample will have higher dispersion in the inferred values of mass, radius and age, due to the absence of atomic diffusion in one of the grids. This can lead to relative uncertainties for individual stars of up to 5% for masses, 2% for radii and 20% for ages. Conclusions. This work shows that a proper modelling of the microscopic transport processes is key for an accurate estimation of their fundamental properties not only for G-type stars, but also for F-type stars. |
| title | Characterisation of FG-type stars with an improved transport of chemical elements |
| topic | Solar and Stellar Astrophysics Earth and Planetary Astrophysics |
| url | https://arxiv.org/abs/2401.14924 |