“Good Vibrations Seminar S3E7”: Nuno Alexandre Martins Moedas (Instituto de Astrofísica e Ciência do Espaço (IA), Portugal)

February 15, 2023 | 10:00 am

Investigating the effect of turbulent mixing in F-type stars.

In stellar evolution one of the fundamental ingredients is the chemical composition. At the stellar surface, the chemical abundances change during the life of the stars due to the presence of the chemical transport mechanisms. One of these processes is atomic diffusion. This process presents great success in simulating solar-type star evolution.
However, for F-type stars, the inclusion of atomic diffusion shows
unrealistic chemical variations at the stellar surface, indicating the need for competing transport processes. In this talk, we present the possibility of parameterizing the effects of the competing processes using the turbulent mixing. We successfully found that it is possible to avoid the chemical over-variations at the stellar surface. We also found that the effects of radiative acceleration in F-type stars can be reproduced using turbulent mixing.
Then we explored the performance of using the parameterised turbulent mixing in the inference of the global properties from a sample of observed Kepler stars. We also compared its results with the current models that neglect atomic diffusion in F-type stars. We found that considering turbulent mixing creates a difference in the inferred age of about 2%.

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