Spectroscopy of the recurrent nova V3890 Sagittarii 18 d after the 1990 outburst

Abstract

The spectrum of the recurrent nova V3890 Sgr, obtained from the Vainu Bappu Observatory 18 d after the 1990 outburst maximum, is presented. The nova was in the coronal line phase. The spectrum is similar to that of the recurrent nova RS Oph. An extinction E(B – V) = 1.1 is derived from the B – V colours, and from Balmer and He I line ratios. From the maximum magnitude-rate-of-decline relations for a nova, M ^v= – 8.6 mag is estimated, which places the nova at a distance of about 5 kpc. Balmer line fluxes are used to derive the density, ∼ 10 ⁹ cm ^-3, and the mass of the ejected ionized shell, ∼10 ^-7 M☉. The temperature and radius estimates for the ionizing source are 3 × 10 ⁵ K and 0.06 R☉. A helium abundance of 0.23 is estimated.