J/AJ/153/238ivo://CDS.VizieR/J/AJ/153/238doi:10.26093/cds/vizier.51530238CDSHan Z.-TQian S.-BIrina V.Zhu L.-Y2017-09-04T08:33:11Z2017-08-10T13:28:15ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.freclipsing-binary-starsDV 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).2017AJ....153..238Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/153/238CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/153/238https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/153/238http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/153/238https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/153/238https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/153/238http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/153/238GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/AJ/153/238/table1All mid-eclipse times of DV UMarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Date of minimum lightdtime.epochdoubleE[1/127225] Epoch numbermeta.id;meta.mainintO-CThe (O-C) residualdstat.fit.residual;stat.fit.omcdoublee_O-CError in O-Cdstat.error;stat.fit.omcdoubleStateState (outburst or quiescence)meta.notecharTelTelescope (1.0m, 2.4m, 85cm)meta.id;instr.telcharRefReference (1)meta.ref;pos.frameint