2006MNRAS.369.1537S -
Mon. Not. R. Astron. Soc., 369, 1537-1546 (2006/July-2)
VW Hyi: optical spectroscopy and Doppler tomography.
SMITH A.J., HASWELL C.A. and HYNES R.I.
Abstract (from CDS):
We present high-quality optical spectroscopy of the SUUMa-subtype dwarf nova, VW Hyi taken while the system was in quiescence. An S-wave is executed by the emission cores of the hydrogen Balmer lines and by the emission lines of Hei, Caii, FeII and Heii. Using Doppler tomography, we show it originates in the accretion stream-disc impact region. The HeII emission is strongly phase-dependent, suggesting it originates exclusively within a hot cavity at the initial impact. We map the ionization structure of the stream-disc interaction region. One possible interpretation of this is that the Balmer hotspot lies downstream of the HeII hotspot in the outer accretion disc, with the Hei and CaII hotspots at intermediate locations between the two. This suggests that Balmer emission is suppressed until material has cooled somewhat downstream of the impact site and is able to recombine. We favour a phase offset of 0.15±0.04 between the photometric ephemeris and inferior conjunction of the mass donor. The white dwarf contributes significantly to the optical continuum, with broad Balmer absorption and narrow Mgiiλ4481 absorption clearly apparent. This latter feature yields the gravitational redshift: vgrav= 38±21 km/s, so M1= 0.71+0.18–0.26 M☉. This implies M2= 0.11±0.03 M☉and hence the donor is not a brown dwarf. A prominent Balmer jump is also observed. We note that the previously accepted system parameters for both VW Hyi and WXHyi incorporate an algebraic error, and we provide a recalculated M1(q) plane for WXHyi.
Abstract Copyright:
2006 The Authors. Journal compilation © 2006 RAS
Journal keyword(s):
accretion, accretion discs - techniques: spectroscopic - stars: dwarf novae - stars: individual: VW Hyi - novae, cataclysmic variables
Simbad objects:
11
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2006MNRAS.369.1537S and select 'bookmark this link' or equivalent in the popup menu