Ultraviolet spectroscopy of symbiotic nova V1016 Cyg with IUE and HST

Abstract

We present International Ultraviolet Explorer (IUE) & Hubble Space Telescope Space Telescope Imaging Spectrograph (HST STIS) observations of the symbiotic nova V1016 Cyg through the period 1978 - 2000. Four spectra at different times revealing the changes in line fluxes are presented. The outflow velocity of the emitting region was calculated to be 900-2000 km s^-1 (FWHM). The reddening of V1016 Cyg was determined from 2200 Å absorption feature to be E (B-V) = 0.36 ± 0.02.

We calculated the fluxes of CIV 1550 Å & CIII] 1909 Å emission lines produced in a stellar wind from the hot white dwarf. We determined the average wind mass loss rate to be ∼2.3 × 10^-6 M_⊙, the average temperature of the emitting region to be ∼1.3 × 10⁵ K, and an average ultraviolet luminosity to be ∼2 × 10³⁵ erg s^-1.

The results show that there are modulations of line fluxes with time. We attributed these spectral modulations to the changes of density and temperature in the emitting region as a result of the variable stellar wind.