The evolution of rotating stars. III. Predicted surface rotation velocities for stars which conserve total angular momentum.
Abstract
Predicted surface rotation velocities for Population I stars at 10, 7, 5, 3, and 1.5 solar masses are presented. The surface velocities were computed for angular momentum with no radial redistribution, complete redistribution, and partial redistribution as predicted by consideration of circulation currents in rotating stars. Near the main sequence, rotational effects can reduce the moment of inertia of a star, so nonrotating models underestimate the expected velocities for evolving stars. On the red giant branch, angular momentum redistribution reduces the surface velocity by a factor of 2 or more, relative to the velocity expected for no radial redistribution. This removes the discrepancy between predicted and observed rotation rates for the K giants and makes it unlikely that these stars lose significant amounts of angular momentum by stellar winds. Calculations indicate that improved observations of the red giants in the Hyades cluster can be used to determine how angular momentum is redistributed by convection
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 1979
- DOI:
- 10.1086/157312
- Bibcode:
- 1979ApJ...232..531E
- Keywords:
-
- Astrophysics;
- Stellar Evolution;
- Stellar Rotation;
- Angular Momentum;
- B Stars;
- Giant Stars;
- Graphs (Charts);
- K Stars;
- Moments Of Inertia;
- O Stars;
- Stellar Models;
- Stellar Winds;
- Astrophysics;
- Giants:Rotation;
- Rotating Stars:Evolution;
- Rotating Stars:Models