Asteroseismology and Stellar Rotation
Abstract
Δ Scuti stars are observed to rotate with surface velocities of the order 100-200 km/s corresponding to a rotation period of about one day. Rotation removes the frequency degeneracy in the azimuthal order m of the modes and thus allows the possibility of determining the angular velocity inside the star. Rotation also perturbs the internal structure of the star, making the star oblate, as well as changing the internal stratification. Such perturbations will result in a systematic change of all frequencies, if compared with a non-rotating star of similar mass and age. In this way even the radial (l = 0) mode frequencies will be affected by the rotation of the star. We discuss how basic properties as well as frequencies of δ Scuti stars are affected by fast rotation and we investigate the impact of these changes on our interpretation of observed frequencies used in an asteroseismic analysis. We discuss the results in the light of the currently available frequency data for δ Scuti stars in the Praesepe cluster.
- Publication:
-
Structure and Dynamics of the Interior of the Sun and Sun-like Stars
- Pub Date:
- 1998
- Bibcode:
- 1998ESASP.418..385K