AAS Meeting #193 - Austin, Texas, January 1999
Session 101. Cataclysmic Variables and Novae
Display, Saturday, January 9, 1999, 9:20am-4:00pm, Exhibit Hall 1

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[101.06] Hydrodynamic Studies of the Evolution of the Extraordinary Nova LMC 1991

S. Starrfield, G.J. Schwarz (ASU), J.W. Truran (Chicago), W.M. Sparks (LANL)

We have performed 1-D hydrodynamic studies, using {\tt NOVA}, of Nova LMC 1991. It was the brightest (mvmax ~ 9) and one of the fastest (t3 = 6 days) novae in the LMC studied with the IUE satellite. Analysis of the IUE spectra found ejection velocities exceeding 3000 km s-1 and indicated that the bolometric luminosity rapidly declined after maximum. UK Schmidt J (4000 - 5400Å) plates established that its rise to maximum was highly unusual in its length, showing behavior more closely resembling a slow nova. A model atmosphere abundance analysis implied that the metallicity of the ejected material was Z = 0.1Z\odot. This value is significantly lower then the canonical LMC metallicity of 1/3 used to successfully analyze LMC 1988 #1 (Schwarz et al. MNRAS, in press, 1998) but is consistent with the position of LMC 1991 which is far from the LMC Bar. There is no indication that the abundances of the ONeMg nuclei are enriched so that the outburst, most likely, occurred on a CO white dwarf. In view of the light curve, ejection velocities, and abundance analysis, we have modeled this explosion by studying accretion of low Z material onto a 1.25M\odot white dwarf. We have used a variety of mass accretion rates and initial white dwarf luminosities and will provide a comparison of our results with the observations. This study extends the methods and physics used in our evolutionary study of Nova V1974 Cyg (Starrfield et al. MNRAS, 296, 502, 1998) to an extragalactic nova.

The author(s) of this abstract have provided an email address for comments about the abstract: sumner.starrfield@asu.edu

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