Modeling CHANDRA Low Energy Transmission Grating Spectrometer Observations of Classical Novae with PHOENIX

We use the PHOENIX code package to model the X‐ray spectrum of Nova V4743 Sagittarii observed with the LETGS onboard the Chandra satellite on 19 March 2003. 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. 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. Preliminary models are calculated assuming solar abundances. It is shown that the models can be used to determine element abundances in the nova ejecta by increasing the absorption in the shell.