Cool Stars 14 - Submitted Abstract # 60
This version created on 05 October 2006

Doppler Imaging with temperature dependent LSD


Silva Jarvinen, Astrophysikalisches Institut Potsdam
Svetlana Berdyugina, Institute of Astronomy ETH-Zentrum

We have developed a new code based on the least-square deconvolution
(LSD) algorithm elaborated previously by Semel (1989, A&A, 225, 456)
and Donati et al.  (1997, MNRAS, 291, 658).  The original method was
used to improve Zeeman signatures in Stokes line profiles by
extracting the polarisation information from as many lines as
possible.  Here we employ Stokes I profiles using all lines which
contain a clear starspot signature in the observed spectra, thus we
can include lines with unknown Lande factor.  To obtain Doppler images
of stellar surfaces the inversion code based on the Occamian approach
(Berdyugina 1998, A&A, 338, 97) has been modified to incorporate LSD
profiles.  For the first time the LSD technique is applied to both
observed line profiles and to a set of local line profiles using the
same mask of spectral lines.  This enables us to get temperature
dependent LSD local line profiles and to overcome the limitations of
the two-temperature approximation previously used with the LSD
technique.  We have tested our method with different spot
distributions and stellar parameters as well as with different noise
levels using simulated spectra.  The method has also been applied to
the observed spectra of active stars.

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