Time-resolved ultraviolet spectroscopy of the cataclysmic variable PG 1711+336.

Abstract

Low-resolution IUE ultraviolet observations of the cataclysmic variable, PG 1711 + 336, are presented. The spectra reveal extensive variability in the wind-formed C IV 1550 A resonance line P Cygni profiles, on time-scales as short as several hours. The high-resolution IUE spectrum of the nova-like system V3885 Sgr, convolved with the IUE low-resolution instrumental profile, provides a good match to the low-resolution wind lines of PG 1711 + 336 at some epochs. Hot-star wind theory and spherical symmetry are assumed in order to model the high-resolution data. The results yield a crude time-independent (lower-limit) estimate for the product of mass-loss rate and ion fraction. Moments of the observed P Cygni profiles in PG 1711 + 336 are measured to quantify the wind variability, and suggest that the C IV wind column densities may vary by a factor of about 2 in about 1 hour. Changes of a factor of about 2 in the edge velocities of the shortward-shifted resonance lines, with maximum values about 4500 km/s, are calculated.