A model of V1016 CYG based on the ultraviolet spectrum.

Abstract

The ultraviolet spectrum of the suspected symbiotic star V 1016 Cygni is interpreted in terms of a single star model. Spectra were obtained at low and high resolutions in the range 1100 to 3200 A by the IUE. From analyses of spectral features including the forbidden Ne V lines, He II UV recombination lines and the continuum flux, an interstellar reddening of 0.41 is derived which corresponds to a distance of 2.2 kpc. Iterative calculations of the parameters of a stellar model with a spherically symmetrical nebular shell are performed to obtain values providing a best fit to the observed spectrum. The results include a stellar temperature of 160,000 K, radius of 0.06 solar radii, with an H(+) region containing 0.00028 solar masses expanding at a rate of 100 km/sec within a much larger neutral hydrogen region expanding at about 40 km/sec. The spectrum is noted to be consistent with that of a very young planetary nebula with excitation temperatures from 8000 to 27,000 K in the H(+) region.