Photoionization modelling of quiescence phase spectra of novae & symbiotic star

TL;DR

This study models the spectra of several novae and a symbiotic star in quiescence using CLOUDY, estimating physical parameters and secondary star contributions based on optical spectra.

Contribution

It provides detailed photoionization models of quiescent nova and symbiotic star spectra, estimating physical conditions and secondary star types for the first time.

Findings

Estimated temperature, luminosity, and hydrogen density of systems.

Identified secondary star types and their spectral contributions.

Modeled spectra with CLOUDY to match observed features.

Abstract

We present results of study, using observed and published spectra in optical region, of few novae (T CrB, GK Per, RS Oph, V3890 Sgr and V745 Sco) in their quiescence phase and a symbiotic star (BX Mon). Observations were made using the facilities available at 2m Himalayan Chandra Telescope (HCT). Generally, the spectra show prominent low ionization emission features of hydrogen, helium, iron and oxygen and TiO absorption features due to the cool secondary component; T CrB and GK Per show higher ionization lines. We used photoionization code CLOUDY to model these spectra. From the best-fit models, we have estimated the physical parameters, e.g., temperature, luminosity & hydrogen density; estimated elemental abundances and other parameters related to the system. By matching the spectra of various giants with the absorption features and from the best-fit, we determined the type of secondaries and also their contribution to the spectra.