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DETECTION OF ORBITAL AND SUPERHUMP PERIODS IN NOVA V 2574 OPHIUCHI

We present the results of 37 nights of CCD unfiltered photometry of nova V2574 Oph (2004) from 2004 and 2005. We find two periods of 0.14164 d ≈ 3.40 h and 0.14773 d ≈ 3.55 h in the 2005 data. The 2004 data show variability on a similar timescale, but no coherent periodicity was found. We suggest that the longer periodicity is the orbital period of the underlying binary system and that the shorter period represents a negative superhump. The 3.40 h period is about 4% shorter than the orbital period and obeys the relation between superhump period deficit and binary period. The detection of superhumps in the light curve is evidence of the presence of a precessing accretion disk in this binary system shortly after the nova outburst. From the maximum magnitude – rate of decline relation, we estimate the decay rate t2 = 17 ± 4 d and a maximum absolute visual magnitude of MV max = –7.7 ± 1.7 mag. Subject headings: accretion, accretion disks — stars: individual: V2574 Oph — novae, cataclysmic variable