Research Note

Rotating stellar models and dynamic tides in close binaries: A first approach

¹ Instituto de Astrofísica de Andalucía, CSIC, Apartado 3004, 18080 Granada, Spain e-mail: claret@iaa.es
² Department of Physics and Astronomy, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK e-mail: B.Willems@open.ac.uk

Corresponding author: A. Claret, claret@iaa.es

Received: 22 April 2003
Accepted: 8 August 2003

Abstract

Rotating stellar models – homogeneous and evolved ones – were introduced for the first time, in order to investigate the effects of rotationally induced changes in the internal structure of stars on the apsidal motion in close binary systems within the framework of the theory of dynamic tides. The rotating models are calculated in the quasi-spherical approximation under the assumption that the star rotates as a solid body. The models show that the spectrum of resonances between dynamic tides and free oscillation modes is substantially modified by rotation. In particular, the changes in the internal structure of the rotating models yield complex spectra which are more than simple images of the spectra in non-rotating models shifted in the period space. An immediate consequence of the differences between rotating and non-rotating models is that a reconsideration of the global problem of the apsidal-motion may be in order.