Infrared observations of the 1985 outburst of RS Ophiuchi.

The authors present 1 - 3.5 μm infrared photometry and spectrosopy of the recurrent nova RS Ophiuchi, obtained during and after its 1985 outburst. In common with the visual light curve, the JHKL fluxes continue their decline past the pre-outburst value, and display a post-outburst minimum before eventual recovery. This behaviour seems to be related to the dispersal and eventual re-appearance of an additional source in the RS Oph system. The infrared spectra suggest the presence of regions at ≡10⁴ and ≡10⁵K in the remnant, consistent with the model for the outburst proposed by Bode & Kahn (1985). Infrared spectroscopy obtained after the outburst had subsided provides clues as to the anomalous infrared colours of RS Oph during quiescence, and to the nature of the secondary.