Spectroscopy of Z Camelopardalis in outburst with the Hopkins Ultraviolet Telescope

Abstract

The Hopkins Ultraviolet Telescope on board the Astro-1 shuttle mission was used to observe the 830-1850 A spectrum of the cataclysmic variable Z Camelopardalis near the peak of a normal outburst. The observation reveals a rich absorption-line and continuum spectrum which peaks near 1050 Å at a flux of 5 × 10-12 ergs cm-2 s-1 A-1. In the sub-Lyα region, some of the stronger absorption lines include S VI λλ933, 945, C III A977, N III λ991, O VI λλ1032, 1038, He II λ1085, P V λλ1118, 1128, and C III λ1176. No emission is observed below the Lyman limit. The continuum spectrum resembles that of an optically thick accretion disk where the integrated spectrum is constructed by summing stellar model atmospheres. Similar models using summed blackbody spectra fail to approximate the observed continuum.