Infrared studies of classical novae and the recurrent nova RS Ophiuchi

Abstract

This work is concerned with new observations, within the 1-100um infrared wavelength range, of novae and with models to explain these and existing observations of these objects.
The first half is concerned with the classical novae. Some of these objects have long been known to be copious producers of dust during outburst. We investigate a possible formation mechanism for this dust - namely nucleation on ions, and we discuss whether such a model can reproduce the observational characteristics of individual novae. IRAS observations of classical novae are also reported. Together with the available ground based observations of these objects the IRAS observations provide valuable information on the nature of such novae. The infrared observations of the nova GQ Mus 1983 are interpreted in terms of free-free radiation from a freely expanding gas shell and a model is constructed in an attempt to reproduce these observations.
The second half is concerned with RS Ophiuchi. This star is a recurrent nova that has undergone five recorded outbursts, the most recent in 1985 January. Extensive photometric and spectroscopic infrared observations were taken during this outburst. These are presented and we attempt to model the observations in terms of a gas shell expanding into a preoutburst circumstellar envelope of material, presumably formed by the wind of the secondary star.