Xi Boo a: Structure and Non-Thermal Heating
Abstract
Xi Boo A is a G8 V star which is substantially more active than the Sun.It is an ideal target for the GHRS instrument which can make observationsof density sensitive emission line ratios and line widths that areimpossible with IUE. We have used our existing observations of xi Boo A,made with IUE, the PSPC and WFC instruments on ROSAT, and EUVE, to makemodels of the atmosphere from the photosphere to the corona, using theMULTI radiative transfer code to model the chromosphere. Discriminationbetween these requires an improved measurement of the electron density.Comparisons of transition region and coronal pressures provide constraintson the geometry, including non-homogeneity. Line widths enter theturbulent pressure and non-thermal energy density, and are required forcomparisons between empirical energy losses and specific heatingmechanisms. Xi Boo A has a measured magnetic field and follows a varietyof field, rotation and line flux correlations found from wider studies ofmain-sequence stars.These can be understood only by elucidating thephysics within a given stellar atmosphere. Xi Boo B can be observedseparately to aid the interpretation of X-ray and EUVE fluxes. We willalso apply for observing time with the HRI on ROSAT.
- Publication:
-
HST Proposal
- Pub Date:
- July 1995
- Bibcode:
- 1995hst..prop.6076J