Superhumps in Cataclysmic Binaries. XIV. V592 Cassiopeiae

We report a spectroscopic and photometric study of the novalike variable V592 Cassiopeiae (=LS I 55 deg 8). The spectrum is that of a typical UX UMa-type star, with weak, narrow Balmer emission superposed on broad absorption. The 0.1-2.2 μm flux distribution also looks fairly normal, suggesting disk accretion at ~10^-8 M_solar yr^-1 and a distance of 330 pc. The emission lines move with P = 0.115063(1) days, which is presumably the underlying orbital period of the binary. Photometry reveals a different period, namely, 0.12228(1) days. The presence of this wave in a short-period cataclysmic variable, and the value of the period excess at 6.3%, suggests identification as a ``permanent superhump.'' After subtraction of this large signal, the residual time series appears to contain a weak feature at 0.11193(5) days. The star evidently shows positive and negative superhumps simultaneously. Its binary period puts it among a modest number of nonmagnetic cataclysmic variables occupying the 2-3 hr period ``gap.''