J/A+A/710/A49ivo://CDS.VizieR/J/A+A/710/A49CDSPoro A.Poggiani R.Foroutanfar A.Harzandjadidi R.Kahali Poor N.,Alicavus F.2026-05-28T07:40:28Z2026-05-28T08:37:23ZCDS support team

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

cds-question@unistra.freclipsing-binary-starsstellar-massesstellar-radiivisible-astronomyThis study explores multiple aspects of W Ursae Majoris (W UMa) contact binary systems with low mass ratios. We provide empirical insights into their definition, structure, rotational stability, and parameter relations. We first examined the range of mass ratios that characterize these systems, and based on an analysis of 818 contact binaries, we established an empirical threshold of q~0.27 to identify systems with a low mass ratio. To investigate the rotational stability, we conducted a Monte Carlo analysis of the squared gyration radii (k1^2^ and k2^2^) and assessed the resulting spin-to-orbital angular momentum ratio (Jspin/Jorb). While k1 remains nearly constant, k2 and Jspin/Jorb decrease slightly with increasing mass ratio. This emphasizes the role of the secondary star's internal structure. Moreover, we compiled a dedicated sample of 115 contact binaries with a low mass ratio and estimated their absolute parameters using Gaia DR3 parallaxes. From this dataset, we derived empirical parameter relations for systems with a low mass ratio that provide a useful reference for future observational and theoretical studies. The resulting datasets and statistical summaries offer benchmarks for modeling, stability evaluation, and evolutionary studies of W UMa-type binaries with low mass ratios.2026A&A...710A..49Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/710/A49CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/710/A49https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/710/A49http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/710/A49https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/710/A49https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/710/A49http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/710/A49GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/710/A49/table3 (New low mass ratio contact binary systems)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/710/A49/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/710/A49/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/710/A49/table3?GETtext/xml+votable180.050000true203.574137539.72062470.0055555555555555566/3 497 689 761 1329 2726 3254 3707 4078 4280 4422 4595 4697 4713 4947 5108 5300 5316 5427 5569 7233 7664 8799 8871 9115 9567 9586 9608 9628 9711 9748 9762 9780 9970 10322 10487 11100 11194 11256 11312 11613 13438 13583 13908 14643 15000 15053 15211 15305 16058 16573 16731 16746 16872 16954 16982 17026 18234 19075 19468 20339 21027 21056 21139 21969 22117 22584 23053 23958 24391 24983 26122 26495 26611 28141 28296 28617 29918 30609 31604 31727 32385 32444 32999 33072 33172 34326 36065 36081 36149 36515 37890 39079 40427 44981 45241 45908 46570 46828 47825 48023 48152 48388 49137https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/710/A49?format=asciiOpticaldefaultJ/A+A/710/A49/table3New low mass ratio contact binary systemsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSubtypeContact-binary subtype (A or W)src.classcharSimbadNameSimbad column added by the CDSmeta.idcharnullable_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainSystemSystem namemeta.id;meta.maincharBibcodeADS bibliographic code of the reference sourcemeta.bib.bibcodecharEclTypeEclipse type (Total or Partial)meta.codecharPeriodOrbital perioddtime.perioddoubleMethodSource/method flag: SP or PHmeta.notecharT1Effective temperature of the primary componentKphys.temperature.effectiveintT2Effective temperature of the secondary componentKphys.temperature.effectiveintqMass ratio used in the literature sourceinstr.setupfloatinvq? Inverse mass ratio, when applicablephys.mass;arith.ratiofloatnullableiOrbital inclinationdegsrc.orbital.inclinationfloatfFillout factorarith.factorfloatl1Luminosity contribution/fraction of the primary componentphys.luminosity;arith.ratiofloatl2Luminosity contribution/fraction of the secondary componentphys.luminosity;arith.ratiofloatr1Fractional radius of the primary componentphys.size.radius;arith.ratiofloatr2Fractional radius of the secondary componentphys.size.radius;arith.ratiofloatl3Third-light flag or contributionmeta.codecharSpotSpot flagmeta.codecharM1Mass of the primary componentsolMassphys.massfloate_M1Uncertainty in M1solMassstat.errorfloatM2Mass of the secondary componentsolMassphys.massfloate_M2Uncertainty in M2solMassstat.errorfloatR1Radius of the primary componentsolRadphys.size.radiusfloate_R1Uncertainty in R1solRadstat.errorfloatR2Radius of the secondary componentsolRadphys.size.radiusfloate_R2Uncertainty in R2solRadstat.errorfloatL1Luminosity of the primary componentsolLumphys.luminosityfloate_L1Uncertainty in L1solLumstat.errorfloatL2Luminosity of the secondary componentsolLumphys.luminosityfloate_L2Uncertainty in L2solLumstat.errorfloatMbol1Bolometric magnitude of the primary componentmagphot.mag.bolfloate_Mbol1Uncertainty in Mbol1magstat.errorfloatMbol2Bolometric magnitude of the secondary componentmagphot.mag.bolfloate_Mbol2Uncertainty in Mbol2magstat.errorfloatlogg1Surface gravity of the primary componentlog(cm.s**-2)phys.gravityfloate_logg1Uncertainty in logg1log(cm.s**-2)stat.errorfloatlogg2Surface gravity of the secondary componentlog(cm.s**-2)phys.gravityfloate_logg2Uncertainty in logg2log(cm.s**-2)stat.errorfloataSemimajor axissolRadphys.angSize.smajAxisfloate_aUncertainty in asolRadstat.errorfloatlogJ0Logarithm of the orbital angular momentumphys.angMomentumfloate_logJ0Uncertainty in logJ0stat.errorfloatAvInterstellar extinction in the V bandmagphys.absorptionfloate_AvUncertainty in Avmagstat.errorfloatBC1Bolometric correction of the primary componentmagphot.mag.bcfloate_BC1Uncertainty in BC1magstat.errorfloatBC2Bolometric correction of the secondary componentmagphot.mag.bcfloate_BC2Uncertainty in BC2magstat.errorfloat