The boundary layer of VW Hyi in quiescence

Details The boundary layer of VW Hyi in quiescence The boundary layer of VW Hyi in quiescence

2004-06-16

arxiv.org/abs/astro-ph/0406370v1

Mon.Not.Roy.Astron.Soc. 361 (2005) 809-812

Astronomy and Astrophysics

Astrophysics

4 pages

Scientific paper

10.1111/j.1365-2966.2005.09209.x

In this letter, we suggest that the missing boundary layer luminosity of dwarf novae in quiescence is released mainly in the ultraviolet (UV) as the second component commonly identified in the far ultraviolet (FUV) as the "accretion belt". We present the well-studied SU UMa-type system VW Hyi in detail as a prototype for such a scenario. We consider detailed multiwavelength observations and in particular the recent FUSE observations of VW Hyi which confirm the presence of a second component (the "accretion belt") in the FUV spectrum of VW Hyi in quiescence. The temperature (50,000K) and rotational velocity (> 3,000km/s) of this second FUV component are entirely consistent with the optically thick region (tau = 1) located just at the outer edge of optically thin boundary layer in the simulations of Popham (1999). This second component contributes 20% of the FUV flux, therefore implying a boundary layer luminosity: $L_{BL} = 2 \times (0.2 \times L_{UV} + L_{X-ray}) = 0.6 \times L_{disc}$, while the theory (Klu\'zniak 1987) predicts, for the rotation rate of VW Hyi's WD, $L_{BL} \approx 0.77 L_{disc}$. The remaining accretion energy ($<0.1 L_{acc}$) is apparently advected into the star as expected for optically thin advection dominated boundary layers. This scenario is consistent with the recent simultaneous X-ray and UV observations of VW Hyi by (Pandel, C\'ordova & Howell 2003), from which we deduced here that the alpha viscosity parameter in the boundary layer region must be as small as $\alpha \approx 0.004$.

Affiliated with

Also associated with

No associations

Rating

The boundary layer of VW Hyi in quiescence does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The boundary layer of VW Hyi in quiescence, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The boundary layer of VW Hyi in quiescence will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-218853