Superhumps in cataclysmic binaries. XVI. DI Ursae Majoris

Robert E. Fried*, Jonathan Kemp, Joseph Patterson, David R. Skillman, Alon Retter, Elia Leibowitz, Elena Pavlenko

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We report photometry of the dwarf nova DI Ursae Majoris during 1997-1998. The star shows an orbital light curve at quiescence with a period of 0.054564(1) days. During superoutburst, it flashes superhumps with a period of 0.05529(5) days. The superhump period excess of 1.3% is quite low among cataclysmic variables, suggesting a weak perturbation on the accretion disk and therefore a secondary of very low mass. But other stars of low period excess are rare eruptors, whereas DI UMa is extremely active with normal outbursts every 8 days and superoutbursts every 30-45 days. This is puzzling. We speculate that the binary really does have a secondary of anomalously low mass but is presently in a high state of a mass-transfer cycle.

Original languageEnglish
Pages (from-to)1275-1280
Number of pages6
JournalPublications of the Astronomical Society of the Pacific
Issue number764
StatePublished - Oct 1999


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