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| Paper: |
Fitting the Chandra LETG Spectrum of SS Cygni in Outburst with Model
Atmosphere Spectra |
| Volume: |
469, 18th European White Dwarf Workshop (EUROWD12) |
| Page: |
349 |
| Authors: |
Suleimanov, V. F.; Mauche, C. W.; Zhuchkov, R. Ya.; Werner, K. |
| Abstract: |
The Chandra LETG spectrum of SS Cyg in outburst shows broad (≈ 5 Å)
spectral features that have been interpreted as a large number of
absorption lines on a blackbody continuum with a temperature of
250 kK (Mauche 2004). It is most probable that this is the spectrum of
the fast-rotating optically thick boundary layer on the white dwarf surface.
Here we present the results of fitting this spectrum with high
gravity hot stellar model atmospheres. An extended set of LTE
model atmospheres with solar chemical composition was computed for
this purpose. The best fit is obtained with the following parameters:
Teff = 190 kK, log g = 6.2, and
NH = 8·1019 cm–2. The spectrum of this model
describes the observed spectrum in the 60–125 Å range reasonably well,
but at shorter wavelengths the observed spectrum has much higher flux.
The reasons for this are discussed.
The derived low surface gravity supports the hypothesis
of the fast rotating boundary layer. |
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