ULTRAVIOLET AND OPTICAL SPECTROSCOPY OF AL-COMAE 1 YEAR AFTER SUPEROUTBURST

We present Hubble Space Telescope (HST) ultraviolet spectra of AL Com obtained with the Faint Object Spectrograph (FOS) during four epochs 1 0-14 months following its 1995 April superoutburst. During our 1996 ob servations, the continuum fluxes underwent a slow decline of 20%, whil e the spectrum showed Ly alpha and Si II absorption features indicativ e of a 20,000 K white dwarf. The cooling sequence in AL Com is found t o be about half as long as that of WZ Sge. This timescale is what is p redicted for an outburst that was half the duration of WZ Sge, if shea r mixing and angular momentum result in nonspherical accretion into an equatorial belt. Our longest data set (1996 June) showed spectral lin e variations on the orbital period with C IV in emission for about one -third of the orbit but revealed no orbital variability in the continu um. Ground-based optical spectra obtained close in time to our Februar y HST data also show stronger line emission for one-third of an orbit and highly variable broad absorption from the secondary star. The spec tral variations may be due to the changing visibility of a nonuniform disk or of a secondary star irradiated by the hot white dwarf.