Model of a Nova Outburst on the Basis of Measurements on V1500 Cygni

Abstract

Spectroscopic and photometric observations of Nova Cygni 1975 yield a temperature curve and a luminosity curve which in turn permit the derivation of the growth of radius of the nova quasi-photosphere. Over a period of about two days the photospheric radius increases from less than 1 R_⊙ to almost 500 R_⊙. Most interesting is the fact that the rate of growth corresponds to a constant acceleration rather than a constant velocity which would be expected if the expansion occurred with the particle velocity of 1500 km sec⁻¹, a value that stayed practically constant over the above-mentioned time interval.