J/ApJ/925/L22ivo://CDS.VizieR/J/ApJ/925/L22doi:10.26093/cds/vizier.19259022CDSLee Y.Kim S.C.Moon D.-S.Park H.S.Drout M.R.Ni Y.QiIm H.2023-12-14T01:21:32Z2023-10-09T12:17:20ZCDS support team

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

cds-question@unistra.frnovaeinfrared-photometryvisible-astronomybroad-band-photometryspectroscopyWe present the first ever discovery of a short-period and unusually helium-deficient dwarf nova KSP-OT-201701a by the Korea Microlensing Telescope Network Supernova Program. The source shows three superoutbursts, each led by a precursor outburst, and several normal outbursts in BVI during the span of ~2.6yr with supercycle and normal cycle lengths of about 360 and 76 days, respectively. Spectroscopic observations near the end of a superoutburst reveal the presence of strong double-peaked HI emission lines together with weak HeI emission lines. The helium-to-hydrogen intensity ratios measured by HeI{lambda}5876 and H{alpha} lines are 0.10+/-0.01 at a quiescent phase and 0.26+/-0.04 at an outburst phase, similar to the ratios found in long- period dwarf novae, while significantly lower than those in helium cataclysmic variables (He CVs). Its orbital period of 51.91+/-2.50 minutes, which is estimated based on time-series spectroscopy, is a bit shorter than the superhump period of 56.52+/-0.19 minutes, as expected from the gravitational interaction between the eccentric disk and the secondary star. We measure its mass ratio to be 0.37_-0.21_^+0.32^ using the superhump period excess of 0.089+/-0.053. The short orbital period, which is under the period minimum, the unusual helium deficiency, and the large mass ratio suggest that KSP-OT-201701a is a transition object evolving to an He CV from a long-period dwarf nova with an evolved secondary star.2022ApJ...925L..22Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/925/L22CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/cb : Cataclysmic Binaries, LMXBs, and related objects (Ritter+, 2004)V/113 : Cataclysmic Binaries, LMXBs, and related objects (Ritter+, 2003)J/MNRAS/460/2526 : Dwarf novae outbursts properties (Otulakowska-Hypka+, 2016)J/ApJ/881/22 : BVI phot of TypeII SN KSP-SN-2016kf (Afsariardchi+, 2019)J/ApJ/910/151 : KMTNet BVi photometry of SNIa KSP-OT-201509b (Moon+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/925/L22https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/925/L22http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/925/L22https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/925/L22https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/925/L22http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/925/L22GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/ApJ/925/L22/fig1KSP-OT-201701a light curves in B, V, and I bandsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJDModified Julian Date (JD-2400000.5)dtime.epochdoubleFilt[BVI] Bandpassmeta.code;instr.filtercharomag[14.97/22.1] Magnitude in Filt, extinction correctedmagphot.mag;arith.difffloate_omag[0.01/0.2] Error of omagmagstat.error;phot.magfloatJ/ApJ/925/L22/fig3Stacked Gemini and Magellan spectra of KSP-OT-201701arecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTelTelescope/Instrument used (1)instr.setupcharlambda[3715.5/9990.4] Wavelength in Angstrom0.1nmem.wlfloatFlux[-0.005/1.2] Flux, 10^-15^erg/s/cm^2^/{AA}1e-08W.m**-3phot.fluxfloatJ/ApJ/925/L22/fig4Radial velocities measured in H{alpha} emissionrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTimeHours from MJD=58158.0htime.epochdoubleRVel[-68/173] Radial velocitykm/sphys.veloc;pos.heliocentricfloate_RVel[23] Error of radial velocitykm/sstat.error;spect.dopplerVelocfloat