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Session 47 - Novae.
Display session, Tuesday, January 14
In April of 1995, the dwarf nova AL Com went into an extended outburst after being at quiescence for 20 yrs. The outburst lasted 2 months in visual light before the system returned to its pre-outburst V mag of 20.1. The large outburst amplitude (8 mag), long recurrence time and outburst length are similar to the system WZ Sge. The UV flux of WZ Sge took over 3 yrs to return to its pre-outburst value, indicating its white dwarf was heated by the outburst. In order to further study the underlying white dwarf in cataclysmic variables, and how it responds to accretion, we used the FOS on HST to obtain UV spectra of AL Com from February-June 1996 (10-14 months past outburst). During this interval, the UV flux declined by 12the spectral distribution was similar to a 20,000K white dwarf. The CIV emission line gradually increased in strength. Surprisingly, optical and UV fluxes show changes in emission and absorption features within the orbital period. This work was supported by NASA grant GO-06489.01-95A.
Program listing for Tuesday