Coronal magnetic fields
Abstract
The use of coronal X-ray emission in determining the configuration of the magnetic field lines in the corona is discussed. Spatially-resolved X-ray observations provided by Skylab and subsequently by missions such as OSO-8 and SMM show the solar corona to be inhomogeneous, with open and closed structures determined by the topology of the magnetic field. The scenario provided by observations from the Einstein, Exosat, and IUE satellites includes the activity in the sun and late-type stars resulting from the emergence of magnetic fields at the star surface. Data demonstrate the dependence of chromospheric and coronal emission on rotation, while there is no evidence that convection zone depths determine the level of magnetic activity, except for early F stars and possibly very late M stars. Results suggest that most late-type dwarfs of all spectral types may have coronae similar to, although often much more active than, the solar corona, and are characterized by confined magnetic structures with typical emission heights significantly smaller than the stellar radius.
- Publication:
-
Highlights of Astronomy
- Pub Date:
- 1986
- Bibcode:
- 1986HiA.....7..447P
- Keywords:
-
- Solar Corona;
- Stellar Coronas;
- Stellar Magnetic Fields;
- X Ray Astronomy;
- Convection;
- Early Stars;
- F Stars;
- Late Stars;
- M Stars;
- Stellar Rotation;
- Astrophysics