Modeling CHANDRA low energy transmission grating spectrometer observations of classical novae with PHOENIX
I. V4743 Sagittarii
Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany e-mail: [apetz;yeti;jness]@hs.uni-hamburg.de
2 Department of Physics and Astronomy, Arizona State University, Tempe, AZ 58287–1504, USA e-mail: email@example.com
Accepted: 1 October 2004
We use the PHOENIX code package to model the X-ray spectrum of Nova V4743 Sagittarii observed with the LETGS onboard the Chandra satellite 19 March 2003. Our atmosphere models are 1D spherical, expanding, line blanketed, and in full non-local thermodynamic equilibrium. To analyze nova atmospheres and related systems with an underlying nuclear burning envelope at X-ray wavelengths, it was necessary to update the code with new microphysics, as discussed in this paper. We demonstrate that the X-ray emission is dominated by thermal bremsstrahlung and that the hard X-rays are dominated by Fe and N absorption. The best fit to the observation is provided at a temperature of Teff = 5.8 105 K, with Lbol = 50 000 . The models are calculated for solar abundances. It is shown that the models can be used to determine abundances in the nova ejecta.
Key words: stars: novae, cataclysmic variables / X-rays: individuals: V4743 Sgr / stars: atmospheres / atomic data
© ESO, 2005