Optical and ultraviolet spectral observations of Nova LMC 1991

We have analyzed the early optically thick ultraviolet and optical (Williams et al 1994) spectra of the fast nova LMC 1991. We used PHOENIX model atmospheres (spherically symmetric, expanding, non-LTE and line-blanketed) to calculate synthetic stellar spectra which were compared to the observations. The fits of the synthetic spectra to the observations were iteratively improved by computing new atmospheres with different parameters. In particular, the fits were significantly improved using a metal abundance of 1/10 solar. They were further improved with carbon and oxygen increased to 10 times solar. Synthetic V band magnitudes calculated from the best fits to each observed spectrum were also consistent with the observed light curve. The bolometric luminosity of the synthetic spectra indicate that Nova LMC 1991 was super-Eddington for approximately one week beyond visual maximum. Assuming a distance of 52 kpc. LMC 1991 reached L-Bol(max) similar to 3 x 10(39) ergs s(-1).