Infrared spectroscopy of Sakurai's object

Abstract

We present near (ground-based) and far (ISO) infrared spectroscopy of Sakurai's object. As in the case of the optical spectrum, between 1996 and 1997 April the near-infrared spectrum underwent a dramatic change to later spectral type, and there is some evidence that the spectrum continued to evolve during 1997. Molecular features of carbon-bearing molecules (CN, C_2, CO) - corresponding to those seen in cool carbon stars - are now prominent in the 1-2.5mum range, and the ^12C/^13C ratio is low. The ISO data demonstrate the presence of hot circumstellar dust at a temperature of ~680K. If the dust shell is optically thin, the dust mass is ~2.8x10^-8Msolar.