Modelling the spectral energy distribution of the red giant in RS Ophiuchi: Evidence for irradiation

Ya V. Pavlenko, B. Kaminsky, M. T. Rushton, A. Evans, Chick E Woodward, L. A. Helton, T. J. O'Brien, D. Jones, V. Elkin

Research output: Contribution to journalArticlepeer-review

Abstract

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 Teff = 3900 K for log g = 2.0, while for log g = 0.0 we find Teff = 4700 K, and a comparison with template stellar spectra provides Teff ~ 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 × 10-6M yr-1) and low (~2 × 10-8M yr-1) accretion rates, respectively. Fits to the accretion disc-extracted infrared spectrum (2008 July 15) yield effective temperatures for the red giant of Teff = 3800 ± 100 K (log g = 2.0) and Teff = 3700 ± 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 twocomponent model atmosphere, in which 90 per cent of the surface has Teff = 3600 K and 10 per cent has Teff = 5000 K. Such structure could be due to irradiation of the red giant by the white dwarf.

Original languageEnglish (US)
Pages (from-to)181-191
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Volume456
Issue number1
DOIs
StatePublished - Feb 11 2016

Bibliographical note

Publisher Copyright:
© 2015 The Authors.

Keywords

  • Binaries: symbiotic
  • Circumstellar matter
  • Novae, cataclysmic variables
  • Stars: individual: RS Oph

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