Detailed Non‐LTE Model Atmospheres for Novae during Outburst. I. New Theoretical Results

Abstract

We present new, detailed non-LTE (NLTE) calculations for model atmospheres of novae during outburst. This fully self-consistent NLTE treatment for a number of model atoms includes 3922 NLTE levels and 47,061 NLTE primary transitions. We discuss the implication of departures from LTE for the strengths of the lines in nova spectra. The new results show that our large set of NLTE lines constitutes the majority of the total line-blanketing opacity in nova atmospheres. Although we include LTE background lines, their e †ects are small on the model structures and on the synthetic spectra. We demonstrate that the assumption of LTE leads to incorrect synthetic spectra and that NLTE calculations are required for reliably modeling nova spectra. In addition, we show that detailed NLTE treatment for a number of ionization stages of iron changes the results of previous calculations and improves the Ðt to observed nova spectra.

Interferometric Observations of V838 Monocerotis

“…Such a large radius cannot be the radius of the white dwarf. In a nova outburst, the system returns to its normal dimension in a few weeks or months-much less than the 3 yr elapsed before our observations (Hauschildt et al 1997;Retter et al 1997;Retter 1999).…”

A Self‐consistent NLTE‐Spectra Synthesis Model of FeLoBAL QSOs

“…PHOENIX is able to model astrophysical plasmas under a variety of conditions, including differential expansion at relativistic velocities , 2006, 2004aHauschildt et al 1997aHauschildt et al , 1997bAllard et al 1997). PHOENIX includes very detailed model atoms constructed from the work of Kurucz Baron et al 1997;Short et al 1999) for a number of almost all the important species (H, He, CNO, Si, Fe, Co, etc.).…”

Project VeSElkA: Vertical Stratification of Element Abundances in CP stars

“…With the aim to estimate the eective temperature, surface gravity and metallicity of stars observed in the frame of the Project VeSElkA, we have generated a new library of high resolution (0.05 Å in the visible range from 3700 Å to 7700 Å) synthetic spectra [30] using version fteen of the PHOENIX code [20].…”