Superhumps in Cataclysmic Binaries. V. V503 Cygni

David Harvey, David Skillman, Joseph Patterson, and Frederick Ringwald

Publications of the Astronomical Society of the Pacific

June 1995, Volume 107, Page 551

We report a radial-velocity study of the dwarf nova V503 Cygni at quiescence, revealing motion of the emission lines with a period of 111.9 ± 0.4 min. This is almost certainly the underlying orbital period of the binary. We also report photometry at all stages of the outburst cycle, which demonstrates a complex pattern of signals. In superoutburst, the star shows a periodic signal at 116.7 ± 0.1 min, which bears all the earmarks of a "superhump," a normal trait of SU UMa-type dwarf nova. During quiescence and short eruptions, the star shows a large-amplitude wave at a period of 109.00 ± 0.02 min--a "negative superhump" since the period shift from P_orb is negative. We interpret the two superhumps as respectively arising from apsidal and nodal precession of the accretion disk.

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Copyright © 1995 Astronomical Society of the Pacific.