Publication Date:
2015-12-16
Description:
We present an analysis of optical and infrared spectra of the recurrent nova RS Oph obtained during between 2006 and 2009. The best fit to the optical spectrum for 2006 September 28 gives T eff = 3900 K for log g = 2.0, while for log g = 0.0 we find T eff = 4700 K, and a comparison with template stellar spectra provides T eff ~ 4500 K. The observed spectral energy distribution (SED), and the intensities of the emission lines, vary on short (1 d) time-scales, due to disc variability. We invoke a simple one-component model for the accretion disc, and a model with a hot boundary layer, with high (~3.9 x 10 –6 M yr –1 ) and low (~2 x 10 –8 M yr –1 ) accretion rates, respectively. Fits to the accretion disc-extracted infrared spectrum (2008 July 15) yield effective temperatures for the red giant of ${T_{\rm eff}}= 3800 \pm 100$ K (log g = 2.0) and ${T_{\rm eff}}= 3700 \pm 100$ K (log g = 0.0). Furthermore, using a more sophisticated approach, we reproduced the optical and infrared SEDs of the red giant in the RS Oph system with a two-component model atmosphere, in which 90 per cent of the surface has T eff = 3600 K and 10 per cent has T eff = 5000 K. Such structure could be due to irradiation of the red giant by the white dwarf.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
Permalink
