Synthetic Spectrum Constraints on a Model of the Cataclysmic Variable QU Carinae

TL;DR

This study develops non-standard accretion disk models for QU Carinae that accurately fit observed spectra across a broad UV range, revealing specific disk temperature structures and constraining system parameters.

Contribution

It introduces non-standard accretion disk models with detailed temperature structures that better match observed spectra of QU Carinae than standard models.

Findings

Non-standard models fit spectra accurately over 900-3000 Å.

Disk hot region extends from white dwarf to 1.36 R_wd.

Orbital inclination between 40° and 60°.

Abstract

Neither standard model SEDs nor truncated standard model SEDs fit observed spectra of QU Carinae with acceptable accuracy over the range 900\AA to 3000\AA. Non-standard model SEDs fit the observation set accurately. The non-standard accretion disk models have a hot region extending from the white dwarf to $R=1.36R_{\rm wd}$,a narrow intermediate temperature annulus, and an isothermal remainder to the tidal cutoff boundary. The models include a range of $\dot{M}$ values between $1.0{\times}10^{-7}M_{\odot} {\rm yr}^{-1}$ and $1.0{\times}10^{-6}M_{\odot} {\rm yr}^{-1}$ and limiting values of $M_{\rm wd}$ between $0.6M_{\odot}$ and $1.2M_{\odot}$. A solution with $M_{\rm wd}=1.2M_{\odot}$ is consistent with an empirical mass-period relation. The set of models agree on a limited range of possible isothermal region $T_{\rm eff}$ values between 14,000K and 18,000K. The model-to-model residuals are so similar that it is not possible to choose a best model. The Hipparcos distance, 610 pc, is representative of the model results. The orbital inclination is between $40\arcdeg$ and $60\arcdeg$.