Search for brown-dwarf like secondaries in cataclysmic variables II

Abstract

We have examined VTL/ISAAC 1-2.5 $\umu$m spectroscopy of a sample of short orbital period cataclysmic variables which are candidates for harboring substellar companions. We provide descriptions of the infrared spectrum of \hbox{EI Psc}, \hbox{V834 Cen}, \hbox{WX Cet}, \hbox{VW Hyi}, \hbox{TY PsA} and \hbox{BW Scl}. Fitting of the IR spectral energy distribution (SED) was performed by comparing the observed spectrum with late-type templates. Absorption features of the secondary star were detected in \hbox{EI Psc} and \hbox{V834 Cen}, consistent with dwarf secondaries of spectral type K 5 $\pm$ 1 and M 8 $\pm$ 0.5, respectively. In addition, we report the first detection of the secondary star in \hbox{VW Hyi}. The SED in this case is well matched by an L 0 $\pm$ 2 type secondary contributing 23 per cent to the overall flux at $\lambda$ = 1.15 $\umu$m. This is a surprising result for a system with a relatively high mass transfer rate. We discuss the implication of our findings on the current scenarios for cataclysmic variable star evolution.

accepted for publication in MNRAS

References in corpus (3)

• On the evidence for brown-dwarf secondary stars in cataclysmic variables
• A search for brown-dwarf like secondaries in cataclysmic variables
• An atlas of line profile studies for SU UMa type cataclysmic variables

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• Spitzer Space Telescope observations of magnetic cataclysmic variables: possibilities for the presence of dust in polars
• VW Hyi: optical spectroscopy and Doppler tomography
• Infrared Spectroscopic Observations of the Secondary Stars of Short Period Sub-Gap Cataclysmic Variables
• The Effect of a Superoutburst on the White Dwarf and Disk of VW Hydri as observed with FUSE
• A brown dwarf donor and an optically thin accretion disc with a complex stream impact region in the period-bouncer candidate BW Sculptoris
• A J-band detection of the sub-stellar mass donor in SDSS J1433+1011