FUSE Spectroscopy of the Accreting Hot Components in Symbiotic Variables

Abstract

We have conducted a spectroscopic analysis of the far ultraviolet archival spectra of four symbiotic variables, EG And, AE Ara, CQ Dra and RW Hya. RW Hya and EG And have never had a recorded outburst while CQ Dra and AE Ara have outburst histories. We analyze these systems while they are in quiescence in order to help reveal the physical properties of their hot components via comparisons of the observations with optically thick accretion disk models and NLTE model white dwarf photospheres. We have extended the wavelength coverage down to the Lyman Limit with FUSE spectra. We find that the hot component in RW Hya is a low mass white dwarf with a surface temperature of 160,000K. We re-examine whether or not the symbiotic system CQ Dra is a triple system with a red giant transferring matter to a hot component made up of a cataclysmic variable in which the white dwarf has a surface temperature as low as $\sim$20,000K. The very small size of the hot component contributing to the shortest wavelengths of the FUSE spectrum of CQ Dra agrees with an optically thick and geometrically thin ($\sim$4\% of the WD surface) hot ($\sim 120,000$K) boundary layer. Our analysis of EG And reveals that its hot component is a hot, bare, low mass white dwarf with a surface temperature of 80-95,000K, with a surface gravity $\log (g)=7.5$. For AE Ara, we also find that a low gravity ($\log (g)\sim 6$) hot ($T\sim 130,000$K) WD accounts for the hot component.

arXiv commentAccepted for publication in the Astronomical Journal. arXiv admin note: substantial text overlap with arXiv:1511.07352

References in corpus (13)

• Validation of the new Hipparcos reduction
• Thermal Equilibria of Accretion Disks
• Measuring White Dwarf Accretion Rates via their Effective Temperatures
• Symbiotic stars in X-rays
• Detailed Mid- and Far-Ultraviolet Model Spectra for Accretion Disks in Cataclysmic Binaries
• Disentangling the composite continuum of symbiotic binaries I. S-type systems
• Swift Observations of Hard X-ray Emitting White Dwarfs in Symbiotic Stars
• The Nature of the Hard-X-Ray Emitting Symbiotic Star RT Cru
• An Online Catalog of Cataclysmic Variable Spectra from the Far Ultraviolet Spectroscopic Explorer
• Wind mass transfer in S-type symbiotic binaries II. Indication of wind focusing
• A Spreading Layer Origin for Dwarf Nova Oscillations
• Symbiotic stars in X-rays III: Suzaku observations
• EG Andromedae: A New Orbit and Additional Evidence for a Photoionized Wind

Cited by in corpus (3)

• Wind mass transfer in S-type symbiotic binaries III. Confirmation of a wind focusing in EG Andromedae from the nebular [OIII]λ5007 line
• Hen 3-860: New southern eclipsing symbiotic star observed in the outburst
• FUSE Spectroscopic Analysis of the Slowest Symbiotic Nova AG Peg During Quiescence