Stars of 2 - 5 M⊙ reside on the main sequence with only extremely weak and narrow surface convection zones suggesting that significant dynamo activity may not be possible. As the stars evolve off the main sequence into the giant domain the convection zone rapidly deepens allowing for the initiation of a dynamo. Evolution into the giant domain also increases the generation of acoustic flux from sub-atmospheric turbulence, the dissipation of which may contribute to chromospheric heating. We discuss the computation of convective turnover time scales for the giant configurations that are structurally quite different from main sequence envelopes. We compare the theoretical expectations for dynamo activity with observations of stellar rotation rates across the HR diagram.
All Science Journal Classification (ASJC) codes
- Aerospace Engineering
- Astronomy and Astrophysics
- Atmospheric Science
- Space and Planetary Science
- Earth and Planetary Sciences(all)