A multiwavelength study of Nova QU vulpeculae 1984

We have combined ground-based optical and satellite ultraviolet spectrophotometric data to study the ejected shell of Nova Vulpecula 1984 No. 2 (QU Vul). Substantial uncertainties concerning the nature of the ionizing continuum, and the role played by density inhomogeneities, now exist. Because of these uncertainties, the chemical composition is deduced from emission-line pairs chosen to minimize the effects of variations in temperature, density, and ionization. We find that the chemical composition of the ejected shell show enhancements of several elements relative to hydrogen, namely, He, N, O, Ne, Mg, Al, and Si, as is expected for an outburst occurring on an ONeMg white dwarf. An almost featureless continuous spectrum and high-ionization lines suggest that a very hot "coronal-line" region is also present, which may contribute to the ionization of the gas and dominate both the mass and the energetics of the ejecta. The total mass of the ejecta is estimated to lie in the range from 0.2 to 15 × 10^-4 M_⊙. This high value of the ejected mass implies a low white dwarfs mass, which is not expected in ONeMg novae. The above results also show that QU Vul ejected a large amount of aluminum into the interstellar medium, and it is estimated that only a small fraction of slow novae of this type can account for the observed abundance of aluminum in the Galaxy.