2004A&A...418..265G -
Astronomy and Astrophysics, volume 418, 265-270 (2004/4-4)
HS 2237+8154: On the onset of mass transfer or entering the period gap?
GAENSICKE B.T., ARAUJO-BETANCOR S., HAGEN H.-J., HARLAFTIS E.T., KITSIONAS S., DREIZLER S. and ENGELS D.
Abstract (from CDS):
We report follow-up observations of a new white dwarf/red dwarf binary HS 2237+8154, identified as a blue variable star from the Hamburg Quasar Survey. Ellipsoidal modulation observed in the R band as well as the Hα radial velocity variations measured from time-resolved spectroscopy determine the orbital period to be Porb=178.10±0.08min. The optical spectrum of HS 2237+8154 is well described by a combination of a Teff=11500±1500K white dwarf (assuming logg=8) and a dM 3.5±0.5 secondary star. The distance implied from the flux scaling factors of both stellar components is d=105±25pc. Combining the constraints obtained from the radial velocity of the secondary and from the ellipsoidal modulation, we derive a binary inclination of i≃50°-70° and stellar masses of Mwd=0.47-0.67M☉ and Msec=0.2-0.4M☉. All observations imply that the secondary star must be nearly Roche-lobe filling. Consequently, HS 2237+8154 may be either a pre-cataclysmic variable close to the start of mass transfer, or - considering its orbital period - a cataclysmic variable that terminated mass transfer and entered the period gap, or a hibernating nova.
Abstract Copyright:
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Journal keyword(s):
stars: binaries: close - stars: individual: HS 2237+8154 - stars: novae, cataclysmic variables
Simbad objects:
5
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