Cool Stars 14 - Submitted Abstract # 152
This version created on 05 October 2006

Building detailed models of the X-ray corona of AB Dor using Chandra
data


G.A.J. Hussain, University of St Andrews
M. University of St Andrews Jardine
J.-F. Donati, Observatoire Midi-Pyrenees
N.S. Brickhouse, SAO
A.K. Dupree, SAO
A. Collier Cameron, University of St Andrews
F. Favata, ESTEC, European Space Agency
K. Wood, University of St Andrews

AB Dor is an active, young rapidly rotating K star that displays
magnetic activity signatures that are typical of those found in many
active cool stars.  We have obtained multi-wavelength data of the star
in order to probe the distribution of active regions, and to determine
how activity is linked between the surface and the corona.  By
extrapolating surface magnetic field maps of AB Dor and fitting the
temperature, density and emission measure evaluated from simultaneous
Chandra X-ray observations we produce detailed models of the X-ray
corona of the star.  Our work indicates that the X-ray emitting corona
is very close to the surface of AB Dor, with a height, H < 0.4R*.  We
show how rotational modulation in the X-ray lightcurves and spectra is
affected by different types of field in the obscured hemisphere (as
the star is inclined at 60  degrees).  The observed X-ray rotational
modulation is then used to build realistic models of the X-ray coronae
of active cool stars for the first time.

----------------------------------