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| Paper: |
Seismic Investigation of Chemical Stratification in Stars |
| Volume: |
462, Progress in Solar/Stellar Physics with Helio- and Asteroseismology |
| Page: |
60 |
| Authors: |
Théado, S. |
| Abstract: |
The chemical elements present in the stellar material are subject,
during stellar evolution,
to various physical processes which tend to build or on the contrary to smooth composition gradients.
The oscillation properties and (often) their excitation mechanism being highly sensitive to the chemical distribution, their detailed analysis offer a unique opportunity to probe
the stellar chemical stratification and to infer information about the internal physics of stars.
In this paper I will first review the case where the chemical distribution acts as a driving or
stabilizing agent for oscillations;
in this context,
I will present the progress in understanding the physics of stars inferred from seismic analyses.
In a second part I will recall, in the case of solar-type stars, the possible asteroseismic tests of internal chemical composition as well as the first attempts to look for these signatures. In the last part I will discuss the effects on stratification and oscillations of an often forgotten process in main-sequence stars, the thermohaline convection. I will show that this double diffusive instability is a fundamental process which may strongly affect the chemical stratification and must then be included in stellar evolutionary computations and derived seismic analysis. |
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