From solar to stellar oblateness

Description

Rotation, and more precisely differential rotation, have a major impact on the internal dynamics of stars (and the Sun) and induce many instabilities driving the transport of angular momentum. In the present paper we shall consider the effects on the shape of shellular layers, and to first order, these concerning the apparent oblateness. The first case concerns the Sun, for which accurate limb fluctuations permit to ascertain not only the oblateness, but also its shape, that it to say the determination of the radius with latitude. Thanks to the advent of interferometry techniques, stellar shapes can be now measured with a great accuracy. We will review here the main results obtained so far on different stars and we will give their physical parameters derived from a model fitting procedure. It will be shown how the core density can be reached.

Abstract

International audience

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