OPTICAL, IUE, AND ROSAT OBSERVATIONS OF THE ECLIPSING NOVA-LIKE VARIABLE V347 PUPPIS (LB-1800)

Using time-resolved optical spectroscopy and UBYRI and high-speed phot ometry obtained at Mount Stromlo Observatory, Mount John University Ob servatory, and the South African Astronomical Observatory; IUE ultravi olet spectroscopy; and ROSAT survey X-ray fluxes, we present a study o f the accretion disk, hot spot, and emission line regions in the brigh t eclipsing nova-like variable V347 Pup (LB 1800). In the optical and UV, V347 Pup is a strong emission line source with a continuum spectru m which is remarkably red for a high-M cataclysmic variable. Consisten t with its high inclination, we interpret the continuum spectrum as th e superposition of the spectrum of the cool (T(eff) almost-equal-to 70 00 K) outer edge and the hot (T(eff) almost-equal-to 100,000 K) inner regions of a self-eclipsed accretion disk. For the assumed parameters, the model matches the level and shape of the observed spectrum for an inclination of almost-equal-to 88-degrees and a distance of almost-eq ual-to 300 pc. The prominent hump in the optical and UV light curves j ust before eclipse manifests the presence of the hot spot where the ac cretion stream strikes the edge of the disk. The wavelength dependence of the amplitude of the hump is best modeled by a spot having an effe ctive temperature of almost-equal-to 25,000 K and an area of almost-eq ual-to 3 x 10(18) cm2 if the spot radiates like a blackbody, or an eff ective temperature of almost-equal-to 14,000 K and an area of almost-e qual-to 3 x 10(19) cm2 if it radiates with a stellar spectrum. In eith er case, the hot spot produces only one-tenth of the predicted luminos ity for the assumed mass-transfer rate of 10(-8) M, yr-1. Either the h ot spot is ''buried'' in the edge of the accretion disk, or a signific ant fraction of its luminosity is radiated away in lines. The differen ce in azimuth between the peak of the hump and the dynamically expecte d location of the hot spot suggests that the spot's emitting surface i s rotated forward by almost-equal-to 36-degrees relative to the edge o f the disk. Phase-resolved optical spectroscopy demonstrates that the optical continuum and emission line regions in V347 Pup have the same radial extent, that the bulk of the Hbeta emission line arises in the accretion disk but that it may also have a modest vertical extent, tha t the He II lambda4686 emission volume is both more sharply defined in the radial coordinate and less extended in the vertical direction, an d that both the Hbeta and He II lambda4686 lines become narrower in ec lipse, consistent with the eclipse of the inner, higher velocity, disk regions. In contrast, phase-resolved IUE spectroscopy demonstrates th at the UV emission lines are only partially occulted in eclipse, indic ating that they are formed in a region with dimensions comparable to t he size of the secondary. Furthermore, the UV emission lines narrow on ly slightly in eclipse and have radial velocities which are delayed in phase relative to the optical emission lines by approximately 0.1 orb ital cycles. The UV lines are modeled (poorly) by resonant scattering of accretion disk photons in a radially expanding wind emanating from the center of the disk. The required long acceleration scale and high wind mass-loss rate, combined with the prediction that the line widths should increase rather than decrease in eclipse, suggest that more co mplicated wind geometries may be necessary to explain the observed pro perties of the UV emission lines, including a possible rotational comp onent near the disk plane and an additional emission component from th e location of the hot spot. Finally, ROSAT survey observations indicat e that V347 Pup is a weak and moderately soft X-ray source. Because of its high inclination, we argue that the X-rays do not come directly f rom the boundary layer but instead come from an extended emission volu me. Possible sources of this emission include soft X-rays produced by shocks in the high-velocity wind and soft boundary layer X-rays which are scattered by the wind into the line of sight.