Superhumps in Cataclysmic Binaries. XIX. DV Ursae Majoris

Joseph Patterson, Tonny Vanmunster, David Skillman, Lasse Jensen, John Stull, Brian Martin, Lewis Cook, and Jonathan Kemp

Publications of the Astronomical Society of the Pacific

December 2000, Volume 112, Page 1584

DV Ursae Majoris is a deeply eclipsing dwarf nova which shows very powerful superhumps when it attains superoutburst. We report detailed observations of the 1997 and 1999 eruptions. In many ways the results reproduce what has been learned from other eclipsing dwarf novae: that the disk becomes very large in outburst; that the superhumping light originates from large radii in the disk; that the shape of the disk appears to change on a timescale of a few days. The mean superhump period was 0.08870(8) d, but in both eruptions the period probably decreased with P-dot=-7×10-5. Globally distributed coverage of the 1997 eruption revealed two other interesting features: evidence of a transient modulation at the orbital period at the peak of eruption, and intricate fine structure in the harmonics of the main superhump signal. In particular, we found that the "second harmonic" occurred not at 3w-3W as expected (where w and W are respectively the orbital and "precession" frequencies), but at 3w-2W and 3w-W.

We also report photometry at quiescence, which separates the luminous contributions of the white dwarf, accretion disk, and secondary star. We derive a distance of 800±300 pc. Analysis of the eclipses suggests i=85±2 °, M₂=0.18±0.03 M_sol, M₁=0.9±0.2 M_sol.

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Copyright © 2000 Astronomical Society of the Pacific.