J/AJ/167/221ivo://CDS.VizieR/J/AJ/167/221doi:10.26093/cds/vizier.51670221CDSJiang S.D.Hillenbrand L.A.2026-07-02T11:44:47Z2024-06-26T07:36:35ZCDS support team

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

cds-question@unistra.fryoung-stellar-objectspre-main-sequence-starsstar-forming-regionsvisible-astronomyMonoceros R2 (Mon R2) is one of the closest large active star-forming regions. This extremely young and partially embedded region provides an excellent laboratory for studying star formation and the early evolution of young stellar objects (YSOs). In this paper, we conduct an optical study of the greater Mon R2 region. Beginning with 1690 previously identified candidate YSOs, we used 496 sources with good proper motions and parallaxes from Gaia Data Release (DR) 3 to determine the astrometric properties for likely members of Mon R2. We then used both astrometric and photometric (isochronal and variability) criteria to determine that 308 of these stars are highly probable members. Using the same criteria, we considered a broad area search around Mon R2 in Gaia DR3 and separated candidate members from field stars. In total, we selected 651 likely new cluster members that had been missed in the previous X-ray and infrared excess selection techniques used in the past to establish cluster membership. Revised astrometric properties of the cluster were found using the combined sample of ~959 highly probable member stars. For the literature plus the new candidate member list, optical light curves were compiled from the Zwicky Transient Facility. For 470 identified variable sources, we attempted classification based on the flux asymmetry (M) and quasiperiodicity (Q) metrics. We find that Mon R2 is dominated by quasiperiodic symmetric variables, with aperiodic sources also a significant population. A few tens of large-amplitude variables are identified that may be of interest for further study.2024AJ....167..221Jhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/167/221CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/337 : Gaia DR1 (Gaia Collaboration, 2016)J/ApJS/94/615 : Molecular outflow sources (Hodapp, 1994)J/AJ/114/198 : The Monoceros R2 Cluster (Carpenter+ 1997)J/ApJ/567/423 : CHANDRA obs. of YSOs in Monoceros R2 (Kohno+, 2002)J/PASJ/55/635 : Chandra observations of Monoceros R2 (Nakajima+, 2003)J/AJ/132/2296 : NICMOS observations of Mon R2 cluster (Andersen+, 2006)J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)J/AJ/144/31 : Spitzer+2MASS photom protostar candidates (Kryukova+, 2012)J/AJ/147/82 : Monitoring of disk-bearing stars in NGC 2264 (Cody+, 2014)J/ApJ/815/4 : V899 Mon long-term monitoring (Ninan+, 2015)J/ApJS/229/28 : SFiNCs X-ray, IR and membership catalogs (Getman+, 2017)J/A+A/607/A22 : Monoceros R2 filament hub FIR observations (Rayner+, 2017)J/ApJ/884/4 : KEYSTONE ammonia structures in Galactic GMCs (Keown+, 2019)J/ApJ/870/32 : Kinematics young star clusters & associations (Kuhn+, 2019)J/MNRAS/483/407 : LMT/AzTEC 1.1mm Survey of Mon R2 dense cores (Sokol+, 2019)J/ApJ/923/171 : V899 Mon opt-NIR spectra and light curves (Park+, 2021)J/AJ/163/263 : 323 YSOs properties with ZTF (Hillenbrand+, 2022)J/MNRAS/524/1826 : Mon R2 photometry (Orcajo+, 2023)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/167/221https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/167/221http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/167/221https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/167/221https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/167/221http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/167/221GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/167/221/table4 (Final members from Literature (YSOC) and new query (Gaia))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/167/221/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/167/221/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/167/221/table4?GETtext/xml+votable180.050000true88.42908-10.438310.005555555555555556Cone search capability for table J/AJ/167/221/table5 (All variable stars and their variability metrics)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/167/221/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/167/221/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/167/221/table5?GETtext/xml+votable180.050000true92.38052-6.312460.0055555555555555565/5361 5364 6/21337 21359 21370 21396 21453 21462 21464-21466https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/167/221?format=asciiOpticaldefaultJ/AJ/167/221/table4Final members from Literature (YSOC) and new query (Gaia)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDObject identifier (1)meta.id;meta.maincharprimaryRAJ2000[88/98] Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000[-11/-4] Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainpmRA[-5.5/-0.6]? Proper motion along RAmas/yrpos.pm;pos.eq.rafloatnullablepmDE[-1.05/3.01]? Proper motion along DEmas/yrpos.pm;pos.eq.decfloatnullableplx[0.54/1.86]? Parallaxmaspos.parallax.trigfloatnullablePISO[0.0/1.0]? Probability membership based on location on Gaia photometry isochronesstat.probabilityfloatnullablePASTRO[0.25/1.0]? Probability membership based on astrometry value in comparison to cluster's median valuesstat.probabilityfloatnullablePVAR[0.0/1.0]? Probability membership based on based on object's variabilitystat.probabilityfloatnullablePTot[0.5/1.0] Total membership probability calculated with weighted averagestat.probabilityfloatfVarThis source is a variable star (link to Table 5)meta.ref.urlcharJ/AJ/167/221/table5All variable stars and their variability metricsIDObject identifier (1)meta.id;meta.maincharPrimaryPrimary QM classification (5)meta.codecharSecondarySecondary classification (6)meta.codecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000[88/94] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-11/-4] Declination (J2000)degpos.eq.dec;meta.mainmagMed[12.95/20.55] Median ZTF light curve magnitudemagphot.mag;em.optfloatmagAvg[12.96/20.55] Average ZTF light curve magnitudemagphot.mag;em.optfloatmagErr[0.01/0.15] Median of the magnitude errormagstat.error;phot.mag;em.optfloatmagStd[0.02/0.79] Standard deviation of the magnitudemagstat.stdev;phot.magfloatmagSkew[-3.68/4.19] Skew or measure of symmetry of magnitudephot.mag;em.optfloatchi2[1.46/3234] Chi-Square of the magnitudestat.fit.chi2floateta[0.0/2.46] Inverse von-neumann statisticstat.fit.paramfloatmKurtKurtosis or "tailedness" of light curve (2)stat.fit.paramcharPer[0.181/284] Highest peak on Lomb-Scargle Periodogram, verified by visual inspectiondtime.periodfloatf_FAPFlag for extreme FAP values (Column added by CDS) (7)meta.codecharFAP[8.33e-154/0.988]? False Alarm Probability calculated by Lomb-Scargle Peridogramstat.probabilitydoublenullableM[-1.22/1.3] M-metric (3)stat.fit.paramfloatQ[0.11/1.01] Q-metric (4)stat.fit.paramfloat