J/A+A/706/A62ivo://CDS.VizieR/J/A+A/706/A62CDSMalhotra S.Castro-Ginard A.Anders F.Jordi C.Donada J.Luri X.,Balaguer-Nunez L.Qin S.Jiang Y.Zupic A.2026-02-02T08:43:30Z2026-02-02T09:27:04ZCDS support team

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

cds-question@unistra.fropen-star-clustersmultiple-starsphotometryvisible-astronomyinfrared-astronomystellar-agesstellar-distancemetallicitystellar-massesextinctiontrigonometric-parallaxUnresolved binaries in star clusters can bias stellar and cluster mass estimates, making their proper treatment essential for studying cluster dynamics and evolution. We aim to develop a fast and robust framework for jointly deriving stellar masses and multiplicity statistics of member stars, together with optimal cluster parameters. We use Gaia DR3 parallaxes together with multi-band photometry of open cluster (OC) members to infer stellar masses and binary mass-ratios through simulation-based inference (SBI), while iteratively fitting the cluster parameters. The validation of our SBI framework on simulated clusters demonstrates that the inclusion of infrared photometry significantly improves the detection of low mass-ratio binaries. The minimum mass-ratio threshold for reliably identifying unresolved binaries depends on cluster properties and the available photometry, but typically lies below q=0.5. Applying our method to 42 well-populated OCs, we derive a catalogue of stellar masses and mass-ratios for 27201 stars, achieving typical uncertainties of 0.08 in q and 0.01M_{Sun}_ in the primary stellar mass. We analyse the archetype OCs M67 and NGC 2360 in detail, including mass segregation and mass-ratio distribution among other characteristics, while deriving multiplicity fractions for the rest of the sample. We find evidence that the high mass-ratio (q=>0.6) binary fraction shows a strong correlation with the age and a weak anti-correlation with the cluster metallicity. Furthermore, the variation of the binary fraction with stellar mass in OCs shows strong accordance with the observed dependence for field stars heavier than ~>0.6M_{Sun}_. Our work paves a path for future population-level investigations of multiplicity statistics and precision stellar masses in extended samples of OCs.2026A&A...706A..62Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/706/A62CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/690/A16 : Nearby open clusters empirical isochroneJ/A+A/686/A42 : Improving the open cluster census. III. (Hunt+, 2024)J/A+A/675/A89 : Multiplicity fractions in Gaia open clusters (Donada+, 2023)J/A+A/673/A155 : StarHorse data for 8 spectroscopic surveys (Queiroz+, 2023)J/A+A/673/A114 : Improving the open cluster census. II. (Hunt+, 2023)J/A+A/672/A29 : 78 Galactic Open cluster structural parametersJ/A+A/649/A178 : NGC6791 V604 Lyr disentangled component spectraJ/A+A/649/A3 : Gaia Early Data Release 3 photometric passbandsJ/A+A/640/A1 : Portrait Galactic disc (Cantat-Gaudin+, 2020)J/A+A/632/A3 : MUSE binaries in NGC 3201 (Giesers+, 2019)J/A+A/623/A108 : Age of 269 GDR2 open clusters (Bossini+, 2019)J/A+A/622/A110 : Spectroscopic membership for NGC 3532 (Fritzewski+, 2019)J/A+A/619/A155 : Open cluster kinematics with Gaia DR2 (Soubiran+, 2018)J/A+A/616/A10 : 46 open clusters GaiaDR2 HR diagramsJ/A+A/437/457 : NGC 2548 uvbyH{beta} and proper motionsJ/A+A/323/139 : K magnitude of Pleiades low-mass binaries (Bouvier+ 1997)J/MNRAS/504/356 : Updated parameters of 1743 open clusters (Dias+, 2021)J/MNRAS/501/4329 : [Fe/H] dependence of the wide-binary fraction (Hwang+, 2021)J/ApJ/921/117 : 43yr spectrosc. monitoring of the Pleiades regionJ/ApJ/901/91 : Sp. obs. of rapidly rotating stars in the PleiadesJ/ApJS/190/1 : A survey of stellar families (Raghavan+, 2010)J/AJ/169/116 : Gaia & 2MASS fitting for Pleiades members (Liu+, 2025)J/AJ/167/12 : Open cluster parameters with ANN (Cavallo+, 2024)J/AJ/165/108 : Properties of 600 bona fide stars in the HyadesJ/AJ/165/45 : (H-W2)-W1 vs W2-(BP-K) for 4 open cluster membersJ/AJ/162/285 : Parameters of 37 binaries in NGC2516 and NGC2422J/AJ/161/190 : Radial Velocities of binary population in M67 (Geller+,2021)J/AJ/161/160 : BINOCS: NEWFIRM & IRAC IR photometry of clustersJ/AJ/157/216 : Stellar multiplicity rate of M dwarfs within 25 pcJ/AJ/151/66 : Velocities of WOCS 24009 and WOCS 40007 in NGC 6819J/AJ/123/1570 : alpha Persei and Praesepe Clusters (Patience+, 2002)V/160 : SHBoost 2024 (Khalatyan+, 2024)VII/233 : 2MASS All-Sky Extended Source Catalog (XSC)II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)I/337 : Gaia DR1 (Gaia Collaboration, 2016)I/354 : StarHorse2, Gaia EDR3 photo-astrometric distancesI/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/706/A62https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/706/A62http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/706/A62https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/706/A62https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/706/A62http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/706/A62GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/706/A62/tablef1 (Cluster parameters and physical properties)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/706/A62/tablef1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/706/A62/tablef1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/706/A62/tablef1?GETtext/xml+votable180.050000true82.18333331.630.005555555555555556Cone search capability for table J/A+A/706/A62/tablef2 (Masses, mass ratios, posteriors and weighted modes parameters of cluster star members)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/706/A62/tablef2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/706/A62/tablef2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/706/A62/tablef2?GETtext/xml+votable180.050000true82.00612281.29825420.0055555555555555564/149 1794 2349 5/587 595 601 604 608-610 624-626 1063 1074 3298 3488 3495 3500 3590-3591 3597 3697 3718-3719 3846-3849 3856-3858 4111 4113 4120-4122 4133 4135 4144 4152 4228 5199 5384 5396 5530 5723 7023 7032 7034 7110-7111 7120-7122 7180 7182-7183 7261 7432 7434-7435 7438 7610 7952-7953 7956 8269 8274-8275 8277 8280 8891 8894 9337 9374 9393 9395 9404-9405 9481 9483-9484 9486 9504 9928 9973 10174 10316-10318 10328-10330 10333 10458 10499 10819 10822 10825 6/855 861 884 892 894-895 945 947 950-951 955-957 959 963 971 978-982 985-990 994 997 1005 1009-1014 1018-1019 1021-1022 1343 1384 1386 1429 1431 1472 1570-1571 1576 1579 1664-1666 1672-1673 1676 2261 2269 2271 2289 2291-2294 2320-2321 2323-2324 2326 2328-2330 2332 2341-2343 2347 2352 2354 2360-2361 2364 2366-2367 2369 2371 2373 2375 2378-2379 2401-2403 2408-2409 2412-2414 2420 2422 2424-2425 2428 2446 2453 2459 2461 2463 2481 2483 2490-2492 2494 2509 2513-2514 2520 2522 2529-2530 2532-2534 2536 2538-2539 2544 2546 2833 4276-4277 4320-4322 8807 8809 8902 8907-8908 8912 8915 8921 8930 8943 8948 8952-8953 8957 9103 9131 9134 9213 10276 10286 10289-10290 10292 10298 10303 10316 10319 10334 10342 10356 10361 10364 10369-10370 10387 10391 10397 10403 10409 10417 10419 10427 10429 10431-10432 10434 10448 10455 10468 10470 10477-10478 10502-10503 10517 10540 10543 10560 10562 10567 10571-10572 10581 10594 10596 10630 10653 10662 10758 10787 13196 13198-13199 13267 13269 13271 13277 13866-13867 13870 13956 13960-13961 13977-13979 13991 14004-14005 14008 14059 14061-14063 14072 14074 14076-14077 14336-14337 14339-14340 14342-14343 14348-14349 14351-14352 14354-14355 14384-14385 14387 14410 14432 14434 14707 14709-14711 14749 14751 14779 14782 14787 14792-14794 14796-14797 14800 14802-14803 14808 14855 14861 14866-14867 14870 14896-14897 14900-14901 14920 14922 15120-15121 15124 15370-15371 15374-15375 15380 15382-15383 15408-15409 15413 15436-15437 15440 15442 15456 16415 16435 16437 16439 16443 16450 16457-16462 16464-16465 16472 16492 16494 16496 16498 16531 16536 16560 16565-16566 16571-16572 16580 16582 16584-16586 16614 16616 16918 16921 16925 16927 16949 16960 16962-16963 16968 20790-20791 20793 20840 20842 20884-20885 20928 21363 21369 21372 21515 21542 21544-21545 21572-21573 21575 21592 22098-22099 22104-22105 22124 22126 22209 22212 22886-22887 22904 22906-22907 22981 22992-22993 24332-24333 24344 26999 27821 27860 27879 27895 27983 27996 28013-28014 28022 28027 28031 28069 28071-28072 28078-28079 28083 28085 28087 28100 28105 28108 28112 28116 28118 28122-28123 28125 28127 28133-28134 28140-28142 28144 28150-28154 28156 28177 28188-28189 28213 28227 28244 28265 28270 28272 28286-28287 28316 28364 28367 28376-28377 28397 28416 28425 28431 28433 28437 28439 28452-28453 28455 28457 28467 28469-28470 28492 28494-28496 28498-28500 28502 28504 28506 28508-28509 28515-28516 28526 28530 28537 28555 28560 28565 28567 28608 28681-28683 28686-28687 28698-28699 28702 28724 28726-28727 28776 28805 28816 29005 29007 29016 29019 29022-29023 29029 29040-29041 29043 29049 29052-29053 29704 29706-29707 29710 29734-29735 29747 29758-29759 29840-29841 29844-29845 29847 29849 29855 29888 29890 29896 29898 29903 30397-30399 30444 30446-30447 30458 31765 31767 31817 31820-31821 31832 33055 33069 33075 33080-33081 33084 33086-33087 33094 33105-33107 33112-33114 33116 33118 33124-33126 33129 33136-33137 33793-33794 35527 35535 35538 35544 35546 35553 35556-35557 35559 35568 35570-35571 37333 37335 37341 37343 37356-37357 37359-37360 37362 37479 37485-37487 37502 37544 37604-37605 37607 37624-37625 37627-37630 37923 37929-37931 37940 37942 38020-38022 38024 38199 38205 38242-38243 38248 38914 38993 38995-38996 38998-38999 39004 39541 39543 39549 39551 39688 39690-39691 39716 39718 39720-39722 39724 39900-39901 39903 40490-40491 40576-40577 40586 40678-40679 40683-40685 40687 40690-40691 41087 41246-41247 41255 41259-41261 41276-41277 41279 41289-41291 41293-41295 41306-41307 41310-41311 41324-41326 41328-41329 41331 41337 41790-41791 41836 41838 41876-41877 41920 41991 41994-41995 42008 42010 42016-42017 42020-42021 42357-42359 42364-42365 43273 433127.952274030004205e-20 1.7798557115773645e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/706/A62?format=asciiOpticalInfrareddefaultJ/A+A/706/A62/tablef1Cluster parameters and physical propertiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameCluster name (Cluster)meta.id;meta.maincharlogAgeMean estimated log(Age) of the cluster (mean_logage)log(yr)time.age;stat.meanfloatDMean estimated distance of the cluster (mean_dist)pcpos.distance;stat.meandoubleSimbadNameSimbad column added by the CDSmeta.idcharnullableAVMean estimated extinction in V band (mean_Av)magphys.absorptionfloat[Fe/H]Value adopted from Joshi et al. (2024FrASS..1148321J) (mean_feh)log(Sun)stat.valuefloatMR1Mass-ratio threshold when infrared photometry is available (q_thresh_gaia_plus)phys.mass;arith.ratiofloatMR2Mass-ratio threshold when only Gaia photometry is available (q_thresh_gaia)phys.mass;arith.ratiofloatN1Total number of detected unresolved binaries above q_thresh_gaia_plus (n_stars_binaries)meta.numberintN2Total number of detected unresolved binaries above q_thresh_gaia (n_stars_binaries_gaia)meta.numberintNNumber of stars in the MS and have G<=19 mag (n_stars_MS)meta.numberintM*lowLowest stellar mass in the catalogue with a mass-ratio estimate (MS_lower_mass)solMassphys.massfloatM*hiHighest stellar mass in the catalogue with a mass-ratio estimate (MS_upper_mass)solMassphys.massfloatHunt2024Display the Improving the open cluster census III of Hunt & Reffert 2024A&A...686A..42H, Cat. J/A+A/686/A42meta.ref.urlchar_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.mainJ/A+A/706/A62/tablef2Masses, mass ratios, posteriors and weighted modes parameters of cluster star membersW1mag? Mean W1-band magnitude (app_W1)magphot.mag;em.IR.3-4umfloatnullableW2mag? Mean W2-band magnitude (app_W2)magphot.mag;em.IR.4-8umfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameCluster name (Cluster)meta.id.parentcharGaiaDR3Gaia DR3 source ID (source_id)meta.id;meta.mainGmagMean G-band magnitude from GaiaDR3 (app_G)magphot.mag;em.optdoubleBPmagMean BP-band magnitude from GaiaDR3 (app_BP)magphot.mag;em.opt.BdoubleRPmagMean RP-band magnitude from GaiaDR3 (app_RP)magphot.mag;em.opt.RdoublePlxMean parallax from GaiaDR3 (parallax)maspos.parallax;stat.meandouble2MASS? Source ID in 2MASS catalogue (designation_2MASS)meta.id.assoccharNN2MASS? Number of neighbours in 2MASS catalogue (number_of_neighbours_2MASS)meta.numberfloatnullableNM2MASS? Number of mates of 2MASS source in Gaia catalogue (number_of_mates_2MASS)meta.numberfloatnullableQ2MASSJHK photometric quality flag (ph_qual_2MASS)meta.code.qual;photcharJmag? Mean J-band magnitude (app_J)magphot.mag;em.IR.JfloatnullableHmag? Mean H-band magnitude (app_H)magphot.mag;em.IR.HdoublenullableKmag? Mean K-band magnitude (app_K)magphot.mag;em.IR.KdoublenullableWISESource ID in AllWISE catalogue (designation_WISE)meta.id.assoccharNNWISE? Number of neighbours in AllWISE catalogue (number_of_neighbours_WISE)meta.numberfloatnullableNMWISE? Number of mates of AllWISE source in Gaia catalogue (number_of_mates_WISE)meta.numberfloatnullableQWISEPhotometric quality flag of WISE passbands (ph_qual_WISE)meta.code.qualcharMassA? Mode of mass_A posterior (mass_A_mode) (1)solMassphys.massfloatnullableMassA16? 16th percentile of mass_A posterior (mass_A_16)solMassphys.massfloatnullableMassA50? 50th percentile of mass_A posterior (mass_A_50)solMassphys.massfloatnullableMassA84? 84th percentile of mass_A posterior (mass_A_84)solMassphys.massfloatnullable[Fe/H]? Mode of [Fe/H] posterior (feh_mode)log(Sun)phys.abund.Fefloatnullable[Fe/H]16? 16th percentile of [Fe/H] posterior (feh_16)log(Sun)phys.abund.Fefloatnullable[Fe/H]50? 50th percentile of [Fe/H] posterior (feh_50)log(Sun)phys.abund.Fefloatnullable[Fe/H]84? 84th percentile of [Fe/H] posterior (feh_84)log(Sun)phys.abund.FefloatnullablelogAge? Mode of log(Age) posterior (logage_mode)log(yr)time.agefloatnullablelogAge16? 16th percentile of log(Age) posterior (logage_16)log(yr)time.agefloatnullablelogAge50? 50th percentile of log(Age) posterior (logage_50)log(yr)time.agefloatnullablelogAge84? 84th percentile of log(Age) posterior (logage_84)log(yr)time.agefloatnullableq? Mode of mass-ratio posterior (q_mode) (2)phys.mass;arith.ratiofloatnullableq16? 16th percentile of mass-ratio posterior (q_16)phys.mass;arith.ratiofloatnullableq50? 50th percentile of mass-ratio posterior (q_50)phys.mass;arith.ratiofloatnullableq84? 84th percentile of mass-ratio posterior (q_84)phys.mass;arith.ratiofloatnullableD? Mode of distance posterior (dist_mode)pcpos.distancedoublenullableD16? 16th percentile of distance posterior (dist_16)pcpos.distancedoublenullableD50? 50th percentile of distance posterior (dist_50)pcpos.distancedoublenullableD84? 84th percentile of distance posterior (dist_84)pcpos.distancedoublenullableAV? Mode of extinction in V band posterior (Av_mode)magphys.absorptionfloatnullableAV16? 16th percentile of extinction in V band posterior (Av_16)magphys.absorptionfloatnullableAV50? 50th percentile of extinction in V band posterior (Av_50)magphys.absorptionfloatnullableAV84? 84th percentile of extinction in V band posterior (Av_84)magphys.absorptionfloatnullableMassAw? Mode of mass_A posterior weighted by cluster parameters (mass_A_weighted_mode)solMassphys.massfloatnullableMassAw16? 16th percentile of mass_A posterior weighted by cluster parameters (mass_A_weighted_16)solMassphys.massfloatnullableMassAw50? 50th percentile of mass_A posterior weighted by cluster parameters (mass_A_weighted_50)solMassphys.massfloatnullableMassAw84? 84th percentile of mass_A posterior weighted by cluster parameters (mass_A_weighted_84)solMassphys.massfloatnullable[Fe/H]w? Mode of [Fe/H] posterior weighted by cluster parameters (feh_weighted_mode)log(Sun)phys.abund.Fefloatnullable[Fe/H]w16? 16th percentile of [Fe/H] posterior weighted by cluster parameters (feh_weighted_16)log(Sun)phys.abund.Fefloatnullable[Fe/H]w50? 50th percentile of [Fe/H] posterior weighted by cluster parameters (feh_weighted_50)log(Sun)phys.abund.Fefloatnullable[Fe/H]w84? 84th percentile of [Fe/H] posterior weighted by cluster parameters (feh_weighted_84)log(Sun)phys.abund.FefloatnullablelogAgew? Mode of log(Age) posterior weighted by cluster parameters (logage_weighted_mode)log(yr)time.agefloatnullablelogAgew16? 16th percentile of log(Age) posterior weighted by cluster parameters (logage_weighted_16)log(yr)time.agefloatnullablelogAgew50? 50th percentile of log(Age) posterior weighted by cluster parameters (logage_weighted_50)log(yr)time.agefloatnullablelogAgew84? 84th percentile of log(Age) posterior weighted by cluster parameters (logage_weighted_84)log(yr)time.agefloatnullableqw? Mode of q posterior weighted by cluster parameters (q_weighted_mode)phys.mass;arith.ratiofloatnullableqw16? 16th percentile of q posterior weighted by cluster parameters (q_weighted_16)phys.mass;arith.ratiofloatnullableqw50? 50th percentile of q posterior weighted by cluster parameters (q_weighted_50)phys.mass;arith.ratiofloatnullableqw84? 84th percentile of q posterior weighted by cluster parameters (q_weighted_84)phys.mass;arith.ratiofloatnullableDw? Mode of dist posterior weighted by cluster parameters (dist_weighted_mode)pcpos.distancedoublenullableDw16? 16th percentile of dist posterior weighted by cluster parameters (dist_weighted_16)pcpos.distancedoublenullableDw50? 50th percentile of dist posterior weighted by cluster parameters (dist_weighted_50)pcpos.distancedoublenullableDw84? 84th percentile of dist posterior weighted by cluster parameters (dist_weighted_84)pcpos.distancedoublenullableAVw? Mode of extinction in V band posterior weighted by cluster parameters (Av_weighted_mode)magphys.absorptionfloatnullableAVw16? 16th percentile of extinction in V band posterior weighted by cluster parameters (Av_weighted_16)magphys.absorptionfloatnullableAVw50? 50th percentile of extinction in V band posterior weighted by cluster parameters (Av_weighted_50)magphys.absorptionfloatnullableAVw84? 84th percentile of extinction in V band posterior weighted by cluster parameters (Av_weighted_84)magphys.absorptionfloatnullableOutlier[0/1]? Flag if star is a photometric outlier (outlier_flag)meta.codeintnullableClusParamCluster parameters estimated using this star (used_in_estimating)meta.codecharSingle? Probability of being a single star (single_star_probability) (4)meta.codefloatnullableNval? Number of samples with non-zero weight when posterior is weighted by cluster parameters (n_valid_samples)meta.numberdoublenullableinMS[0/1]? Flag if star is in the main-sequence (MS) and has app_G <= 19 mag (in_MS)meta.codeintnullableqthrMass-ratio threshold above which a star is considered an unresolved binary (q_thresh_used)phys.mass;arith.ratiofloatqadop? Adopted mass-ratio value, Set to q_weighted_mode if => 'q_thresh_used' for stars with 'in_MS' = 1, otherwise 0 or NaN (q_adopted)phys.mass;arith.ratiofloatnullablee_qadop? Difference between 84th and 16th percentiles of weighted q posterior (q_adopted_error)stat.errorfloatnullable_RAPosition from I/355/gaiadr3 GaiaDR3 catalog (right ascension part)degpos.eq.ra;meta.mainindexed_DEPosition from I/355/gaiadr3 GaiaDR3 catalog (declination part)degpos.eq.dec;meta.mainindexedPhot? Observed photometry used to sample the SBI posterior (Posterior_used) (3)meta.codechar