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Using Chandra/LETG Spectra to Probe Stellar Coronae

Published online by Cambridge University Press:  26 May 2016

Gaitee A. J. Hussain ,
Nancy Brickhouse ,
A. K. Dupree ,
Adriaan A. van Ballegooijen ,
Andrew Collier Cameron ,
Moira Jardine  and
Jean-Francois Donati
Gaitee A. J. Hussain
Affiliation:
ESTEC, ESA, P.O. Box 299, 2200 AG, Noordwijk, The Netherlands
Nancy Brickhouse
Affiliation:
Harvard Smithsonian CfA, 60 Garden St, Cambridge MA02138, USA
A. K. Dupree
Affiliation:
Harvard Smithsonian CfA, 60 Garden St, Cambridge MA02138, USA
Adriaan A. van Ballegooijen
Affiliation:
Harvard Smithsonian CfA, 60 Garden St, Cambridge MA02138, USA
Andrew Collier Cameron
Affiliation:
School of Physics & Astronomy, Univ. of St Andrews, Fife, UK
Moira Jardine
Affiliation:
School of Physics & Astronomy, Univ. of St Andrews, Fife, UK
Jean-Francois Donati
Affiliation:
Laboratoire d'Astrophysique, Observ. Midi-Pyrénées, Toulouse, France

Abstract

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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 Prot and find evidence of rotational modulation (max. vel. ∼ 40 ± 13km s—1). This modulation may indicate the presence of a localised X-ray emitting region at mid-to-high latitudes.

Type
Part 6: Low Mass Stellar Magnetic Activity and Evolution
Information
Symposium - International Astronomical Union , Volume 219: Stars as Suns : Activity, Evolution and Planets , 2004 , pp. 301 - 305
Copyright
Copyright © Astronomical Society of the Pacific 2004 

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