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Description
DV UMa is an eclipsing dwarf nova with an orbital period of ~2.06hr, which lies just at the bottom edge of the period gap. To detect its orbital period changes, we present 12 new mid-eclipse times by using our CCD photometric data and archival data. The latest version of the O-C diagram, combined with the published mid-eclipse times in quiescence, and spanning ~30 years, was obtained and analyzed. The best fit to those available eclipse timings shows that the orbital period of DV UMa is undergoing a cyclic oscillation with a period of 17.58(+/-0.52) years and an amplitude of 71.1(+/-6.7) s. The periodic variation most likely arises from the light-travel-time effect via the presence of a circumbinary object, because the required energy to drive the Applegate mechanism is too high in this system. The mass of the unseen companion was derived as M_3_sini'=0.025(+/-0.004)M_{Sun}_. If the third body is in the orbital plane (i.e., i'=i=82.9{deg}) of the eclipsing pair, this would indicate it is a brown dwarf. This hypothetical brown dwarf is orbiting its host star at a separation of ~8.6 au in an eccentric orbit (e=0.44).
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