## Rapidly rotating stars with either H burning or He burning core
^{1} Department of Physics, Kyushu University, Ropponmatsu,
Fukuoka 810, Japan^{2} Department of Earth Science and Astronomy, University of
Tokyo, Komaba, Tokyo 153, Japan^{3} Max-Planck-Institut für Astrophysik
Karl-Schwarzschild-Str.1, D-85740, Garching, Germany
We have succeeded in constructing structures of realistic models for rapidly rotating inhomogeneous stars in the nuclear burning stages. The nuclear reaction networks both for CNO cycle and for helium burning have been successfully included in the 2D numerical code. Concerning the equation of state and the opacity, we have used the same ones as used in calculations of spherical stellar structures. The rotation law in our computations covers uniform rotation and differential rotation with rapidly rotating cores. We have computed several equilibrium sequences of massive stars up to models just before the mass begins to shed from the equatorial surface (critical models). We mainly discuss two critical sequences of models: 1) 18
stars with hydrogen burning cores and 2) 5
helium stars with helium burning cores. It is
found that the effect of rotation on the structure is similar for both
sequences. For uniformly rotating hydrogen burning stars the
luminosity decrease is about 6.4% which is consistent with the results
obtained by other authors. For models which have the angular momentum
distribution concentrated toward the center, we get very flattened
shapes of stellar surfaces. Compared with the non-rotating models,
decrease of the luminosity is found to be 16% for the critical models
if the total angular momentum is less than 10
## Contents- 1. Introduction
- 2. Assumptions and numerical methods
- 2.1. Assumptions
- 2.2. Input physics
- 2.3. Basic equations and boundary conditions
- 2.4. Equations in the temperature space
- 2.5. Rotation law
- 2.6. Numerical scheme
- 3. Initial models
- 4. Results
- 5. Discussions and concluding remarks
- Acknowledgements
- References
© European Southern Observatory (ESO) 1997 Online publication: April 20, 1998 |