VLBI observations of RS Oph – a recurrent nova with non-spherical ejection

Abstract

VLBI observations of the recurrent nova RS Oph were performed following its 1985 outburst. Measurements were carried out 40 days after optical maximum at a frequency of 5 GHz on the single 700-km baseline from Jodrell Bank to Effelsberg, and at 1.7 GHz with four stations of the European VLBI network. The analysis suggests that the dual-component radio spectrum of RS Oph is composed of a rapidly evolving low-frequency nonthermal component together with a high-frequency thermal component which reaches peak flux density much later than the nonthermal emission.