J/AJ/157/85ivo://CDS.VizieR/J/AJ/157/85doi:10.26093/cds/vizier.51570085CDSBriceno C.Calvet N.Hernandez J.Vivas A.K.Mateu C.Downes J.J.,Loerincs J.Perez-Blanco A.Berlind P.Espaillat C.Allen L.,Hartmann L.Mateo M.Bailey III J.I.2021-10-01T08:57:13Z2019-06-06T14:19:37ZCDS support team

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

cds-question@unistra.frstellar-associationspre-main-sequence-starssurveysvariable-starsline-intensitiesinfrared-photometryvisible-astronomyphotometryWe present results of our large-scale, optical, multi-epoch photometric survey across ~180 square degrees in the Orion OB1 association, complemented with extensive follow-up spectroscopy. Our focus is mapping and characterizing the off-cloud, low-mass, pre-main-sequence (PMS) populations. We report 2062 K- and M-type confirmed T Tauri members; 59% are located in the OB1a subassociation, 27% in the OB1b subassociation, and the remaining 14% in the A and B molecular clouds. We characterize two new clusterings of T Tauri stars, the HD 35762 and HR 1833 groups, both located in OB1a not far from the 25 Ori cluster. We also identify two stellar overdensities in OB1b, containing 231 PMS stars, and find that the OB1b region is composed of two populations at different distances, possibly due to the OB1a subassociation overlapping with the front of OB1b. A ~2 deg wide halo of young stars surrounds the Orion Nebula Cluster, corresponding in part to the low-mass populations of NGC 1977 and NGC 1980. We use the strength of H{alpha} in emission, combined with the IR excess and optical variability, to define a new type of T Tauri star, the C/W class, stars we propose may be nearing the end of their accretion phase, in an evolutionary state between classical and weak-lined T Tauri stars. The evolution of the ensemble-wide equivalent width of Li I{lambda}6707 indicates a Li depletion timescale of ~8.5 Myr. Disk accretion declines with an e-folding timescale of ~2 Myr, consistent with previous studies.2019AJ....157...85Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/157/85CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/36 : UBV and uvby-beta observations of Orion OB1 AssociationJ/A+A/289/101 : Orion OB1 association. I. (Brown+, 1994)J/ApJS/101/117 : UBVRIJHKLMNQ photometry in Taurus-Auriga (Kenyon+ 1995)J/AJ/127/1158 : QUEST RR Lyrae Survey first catalog (Vivas+, 2004)J/AJ/129/907 : New Ori OB1 members (Briceno+, 2005)J/AJ/131/2959 : Candidate low-mass PMS in 25 Orionis group (McGehee+, 2006)J/ApJ/646/297 : Spitzer obs. of pre-main-sequence stars (Rebull+, 2006)J/ApJ/661/1119 : Spectroscopy in the 25 Ori group (Briceno+, 2007)J/ApJ/671/1784 : Ori OB1 IRAC/MIPS observations (Hernandez+, 2007)J/AJ/144/192 : Spitzer survey of Orion A and B. I. YSO catalogJ/A+A/572/A89 : Young stellar object candidates toward OrionJ/MNRAS/444/1793 : 25 Ori group low-mass stars (Downes+, 2014)J/AJ/152/198 : Periods of 4-10 Myr old T Tauri members of Orion OB1J/ApJ/818/59 : IN-SYNC. IV. YSOs in Orion A (Da Rio+, 2016)J/A+A/608/A148 : Stellar populations towards Orion with Gaia DR1J/AJ/153/188 : Spectroscopy of the foreground population in Orion AJ/AJ/154/14 : Low-mass stars in 25 Ori group and Orion OB1ahttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/157/85https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/157/85http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/157/85https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/157/85https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/157/85http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/157/85GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/157/85/table1 (CVSO observing log)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/157/85/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/157/85/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/157/85/table1?GETtext/xml+votable180.050000true67.51.00.005555555555555556Cone search capability for table J/AJ/157/85/table2 (WIYN-Hydra and MMT-Hectospec observing log)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/157/85/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/157/85/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/157/85/table2?GETtext/xml+votable180.050000true78.5-0.41750.005555555555555556Cone search capability for table J/AJ/157/85/table3 (T Tauri stars in the CVSO)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/157/85/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/157/85/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/157/85/table3?GETtext/xml+votable180.050000true77.74491667-0.134194440.0055555555555555564/1430 5/5359 5369 5699 5701-5703 5709-5712 5714-5715 5718 5724 5726-5727 5733 5744-5745 5748 5890 6/17391 17400 17631 17695 17705 17715-17716 17720 17736 17741 17752 17768 17967 17972 17976 18671 18739 18772 18788 18820 19012 21435 21453-21455 21466 21473-21474 21480 21482 21484 21486 21490-21491 21503 21795 22058 22735 22742 22761 22767 22776 22781 22791 22800 22802-22803 22820-22821 22823 22826 22828-22829 22831-22834 22852 22854-22855 22865-22870 22876 22879 22900 22902-22903 22915-22916 22920 22926 22928-22930 22941 22945 22947 22957 22962 22964-22965 22967 22971-22972 22986 22989 22991 22996 22998 23001 23008-23010 23012-23013 23025 23069 23071 23092 23096 23107 23122 23137 23171-23172 23176 23181 23192 23208 23296 23312 23317-23318 23552 23564 23566 23584 23586-23587 23592 36831 36847 36851 368568.650015785639275e-20 3.852589004194616e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/157/85?format=asciiOpticalInfrareddefaultJ/AJ/157/85/table1CVSO observing logrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of the observationtime.epochnullableNum[300/809] Observation numbermeta.idintDEJ2000Degree of central Declination of drift scan observation (J2000)degpos.eq.dec;meta.mainRAJ2000Degree of Right Ascension of the beginning of drift scan observation (J2000)degpos.eq.raRAdeg2Degree of Right Ascension of the end of drift scan observation (J2000)degpos.eq.ra;meta.mainFiltFilter(s) usedinstr.setup;instr.filtercharHAHour angle (1)pos.eq.hanullableHAs[0ENW-] Hour angle sidepos.eq.hacharJ/AJ/157/85/table2WIYN-Hydra and MMT-Hectospec observing logrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of the observationtime.epochnullableInstInstrument usedinstr.setupcharFieldField identifier (1)meta.id;obs.fieldcharRAJ2000Center Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Center Degree of Declination (J2000)pos.eq.dec;meta.mainTexpExposure timestime.duration;obs.exposurecharNobj[24/277] Number of objectsmeta.numberintNoteAdditional notemeta.notecharBibcodeBibcode of the reference in Notemeta.bib.bibcodecharJ/AJ/157/85/table3T Tauri stars in the CVSOSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCVSOThe CVSO numbermeta.id;meta.maincharH07[9/2386]? Source identification from Hernandez et al. (2007, J/ApJ/671/1784), [HCB2007] OB1a NNNN in Simbadmeta.idintnullableONameOther designation(s) from SIMBADmeta.idcharRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainSpTypeSpectral typesrc.spTypecharEWHa[-400/0.81] Equivalent width of H{alpha} {lambda}6563 ({AA})0.1nmspect.line.eqWidthdoubleEWLiI[0/1.6]? Equivalent width of Li I {lambda}6707 ({AA})0.1nmspect.line.eqWidthfloatnullableEWNaI[0.088/4.452]? Equivalent width of Na I {lambda}8200 ({AA})0.1nmspect.line.eqWidthfloatnullableTypeT Tauri classification type (1)src.classcharVmagmean[13.248/20.489]? V band robust mean magnitude (2)magphot.mag;em.opt.Vfloatnullablee_Vmagmean[0.001/0.57]? 1{sigma} error in Vmagmeanmagstat.errorfloatnullableo_Vmagmean[0/140] Number of measurements in Vmagmeanmeta.numberintRcmagmean[13.218/19.697]? Cousins R band robust mean magnitude (2)magphot.mag;em.opt.Rfloatnullablee_Rcmagmean[0/0.118]? 1{sigma} error in Rcmagmeanmagstat.errorfloatnullableo_Rcmagmean[0/96] Number of measurements in Rcmagmeanmeta.numberintIcmagmean[11.83/18.811]? Cousins I band robust mean magnitude (2)magphot.mag;em.opt.Ifloatnullablee_Icmagmean[0/0.365]? 1{sigma} error in Icmagmeanmagstat.errorfloatnullableo_Icmagmean[0/152] Number of measurements in Icmagmeanmeta.numberintAmpV[0/3.582]? V-band peak-to-peak amplitudemagsrc.var.amplitudefloatnullableAmpRc[0/3.048]? R_c_-band peak-to-peak amplitudemagsrc.var.amplitudefloatnullableAmpIc[0/2.457]? I_c_-band peak-to-peak amplitudemagsrc.var.amplitudefloatnullableVstd[0/1.034]? V-band standard deviationmagstat.stdev;phot.magfloatnullableRcstd[0/0.692]? R_c_-band standard deviationmagstat.stdev;phot.magfloatnullableIcstd[0/0.691]? I_c_-band standard deviationmagstat.stdev;phot.magfloatnullableVprob? {chi}^2^ probability of variability in Vsrc.varcharRcprob? {chi}^2^ probability of variability in R_c_src.varcharIcprob? {chi}^2^ probability of variability in I_c_src.varcharLVRc[-4.858/37.717]? Stetson variability index for V and R_c_ magnitudes (2)meta.code;src.var.indexfloatnullableLVIc[-3.038/65.035]? Stetson variability index for V and I_c_ magnitudes (2)meta.code;src.var.indexfloatnullableLRcIc[-4.114/45.403]? Stetson variability index for R_c_ and I_c_ magnitudes (2)meta.code;src.var.indexfloatnullableJmag[8.77/17.009]? 2MASS J band magnitudemagphot.mag;em.IR.Jfloatnullablee_Jmag[0.019/0.195]? 2MASS 1{sigma} combined error in Jmagmagstat.error;phot.magfloatnullableHmag[7.781/16.148]? 2MASS H band magnitudemagphot.mag;em.IR.Hfloatnullablee_Hmag[0.02/0.234]? 2MASS 1{sigma} combined error in Hmagmagstat.error;phot.magfloatnullableKsmag[7.451/16.044]? 2MASS K_s_ band magnitudemagphot.mag;em.IR.Kfloatnullablee_Ksmag[0.018/0.23]? 2MASS 1{sigma} combined error in Ksmagmagstat.error;phot.magfloatnullableTeff[0/5575] Effective temperature (3)Kphys.temperature.effectiveintAv[0/5.672] Extinction in V band (4)magphys.absorptionfloatLocLocation within the Orion OB1 associationmeta.id.parentchar