The Evolution of Classical Novae in the Ultraviolet

Abstract

During the more than sixteen years since its launch the IUE satellite has observed the outbursts of a large number of Classical Novae. An examination of the large database built up during these years shows that the number of spectra available for each of the objects is highly variable, depending on the brightness, the rate of decline, spacecraft constraints, etc. Attending to the number and time distribution of the existing spectra, the CNe observed with IUE can be grouped into four categories:

• Objects which have been well followed during and after outburst. Belonging to this group are: V1668 Cyg 1978 (the first nova observed with IUE, Stickland et al.1981), GQ Mus 1983 (the nova which has been observed with IUE for the longest period -11 years-, Krautter et al. 1984), PW Vul 1984 (Andreä et al. 1991), QU Vul 1984 (Saizar et al. 1992), OS And 1986 (Starrfield et al. 1988) and V838 Her 1991 (Starrfield et al. 1992). Three extragalactic novae, LMC 1988 No. 1 (Sonneborn et al. 1988), LMC 1988 No.2 (González-Riestra and Cassatella 1988) and LMC 1991 (González-Riestra et al. 1991) have been observed during the first year after the outburst.

• Other objects were well observed during the first stages of the outburst (weeks or months), but there is not any observation at later phases. In this category are V694 CrA 1981 (Williams et al. 1985), V1370 Aql 1982 (Snijders et al. 1987), LMC 1990 No. 1 (Shore et al. 1990) and LMC 1992 (Shore et al. 1992)

• For some objects there are very few observations, either during the outburst and/or at later stages (e.g. V842 Cen 1986 or QV Vul 1987).

• At the time of writing (June 1994) three objects are being regularly observed with IUE: V351 Pup 1991, V1974 Cyg 1992 (Shore et al. 1994a) and Nova Cas 1993 (Shore et al. 1994b).