Using Chandra/LETG spectra to probe stellar coronae
Abstract
We probe the relationship between surface magnetic fields and the X-ray emitting corona in the rapidly rotating star AB Dor. Circularly polarised spectra have been inverted to produce a surface (photospheric) magnetic field map. This surface map has been extrapolated to model AB Dor's coronal field topology and X-ray light curve. Chandra/LETG light curves of AB Dor from the same epoch show intrinsic variability at the 30% level. Period analysis indicates a fraction of this is due to rotational modulation. We measure velocity shifts in emission line centroids as a function of rotation period and find evidence of rotational modulation (max. vel. ~40+/- 13km/s). This modulation may indicate the presence of a localised X-ray emitting region at mid-to-high latitudes.
Cite
@article{arxiv.astro-ph/0403215,
title = {Using Chandra/LETG spectra to probe stellar coronae},
author = {Gaitee A. J. Hussain and Nancy Brickhouse and Andrea K. Dupree and Adriaan A. van Ballegooijen and Andrew Collier Cameron and Moira Jardine and Jean-Francois Donati},
journal= {arXiv preprint arXiv:astro-ph/0403215},
year = {2009}
}
Comments
6 pages, Conference proceedings: IAU Symposium 219. Stars as Suns: Activity, Evolution, Planets, eds. A.K. Dupree & A.O. Benz, (San Francisco: ASP) in press