J/AJ/161/87ivo://CDS.VizieR/J/AJ/161/87doi:10.26093/cds/vizier.51610087CDSDickson-Vandervelde D.A.Wilson E.C.Kastner J.H.2021-07-05T13:34:53Z2021-05-25T08:28:23ZCDS support team

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

cds-question@unistra.frstellar-associationspre-main-sequence-starsradial-velocityproper-motionsvisible-astronomytrigonometric-parallaxinfrared-photometryThe precise parallax, proper motion, and photometric measurements contained in Gaia Data Release 2 (DR2) offer the opportunity to reexamine the membership and ages of nearby young moving groups (NYMGs), i.e., loose groups of stars of age <~100Myr in the solar vicinity. Here, we analyze the available DR2 data for members and candidate members of the {epsilon}Cha Association ({epsilon}CA) which, at an estimated age of ~3-5Myr, has previously been identified as among the youngest NYMGs. The several dozen confirmed members of {epsilon}CA include MPMus and TCha, two of the nearest stars of roughly solar mass that are known to host primordial protoplanetary disks, and the Herbig Ae/Be star HD104237A. We have used Gaia DR2 data to ascertain the Galactic positions and kinematics and color-magnitude diagram positions of {epsilon}CA members and candidates so as to reassess their membership status and thereby refine estimates of the distance, age, multiplicity, and disk fraction of the group. Our analysis yields 36 bona fide {epsilon}CA members, as well as 20 provisional members, including 3 new members identified here as comoving companions to previously known {epsilon}CA stars. We determine a mean distance to {epsilon}CA of 101.0{+/-}4.6pc and confirm that, at an age of 5_-2_^+3^Myr, {epsilon}CA represents the youngest stellar group within ~100pc of Earth. We identify several new photometric binary candidates, bringing the overall multiplicity fraction (MF) of {epsilon}CA to 40%, intermediate between the MFs of young T associations and the field.2021AJ....161...87Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/161/87CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIII/272 : RAVE 4th data release (Kordopatis+, 2013)I/337 : Gaia DR1 (Gaia Collaboration, 2016)I/345 : Gaia DR2 (Gaia Collaboration, 2018)VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)J/A+A/460/695 : Search for Associations Containing Young stars (Torres+, 2006)J/A+A/551/A46 : Compiled photometry for ChamI & II members (Lopez Marti+,2013)J/MNRAS/435/1325 : Membership of the {epsilon} Cha association (Murphy+, 2013)J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars (Pecaut+, 2013)J/ApJ/788/81 : BANYAN III. RVel and rotation of low-mass stars (Malo+, 2014)J/MNRAS/454/593 : Young moving groups in solar neighbourhood (Bell+, 2015)J/A+A/573/A126 : VLT/NaCo Large program I. Sample (Desidera+, 2015)J/AJ/154/195 : New binaries in the {epsilon} Cha association (Briceno+, 2017)J/ApJ/862/138 : BANYAN. XIII. Nearby young assoc. with Gaia DR2 (Gagne+, 2018)J/ApJ/856/23 : BANYAN. XI. The BANYAN {Sigma} algorithm (Gagne+, 2018)J/AJ/157/234 : ACRONYM. III. Candidate young low-mass stars (Schneider+,2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/161/87https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/161/87http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/161/87https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/161/87https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/161/87http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/161/87GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/161/87/table1 (Gaia data for candidate {epsilon}ChA members)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/161/87/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/161/87/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/161/87/table1?GETtext/xml+votable180.050000true142.141256-78.193790.0055555555555555565/9280 9284 6/36884 36946 36947 36948 36949 36956 36969 37125 37127 37173 41122 41128 41130 41135 41472 41473 41474 41481 41484 41505 41515 41518 41519 41526 41528 41600 41601 41603 41605 416121.1166583743361574e-19 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/161/87?format=asciiOpticalInfrareddefaultJ/AJ/161/87/table1Gaia data for candidate {epsilon}ChA membersSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar identifiermeta.id;meta.maincharprimaryf_NameFlag on Name (1)meta.codecharRAJ2015[142/201] Degree of Right Ascension (J2015.5)degpos.eq.ra;meta.mainDEJ2015[-85/-68] Degree of declination (J2015.5)degpos.eq.dec;meta.mainplx[1.56/11.99]? Parallaxemaspos.parallax.trigfloatnullablee_plx[0.02/1]? Error on plxmasstat.error;pos.parallaxfloatnullableGmag[4.78/17.2] G-band magnitudemagphot.mag;em.optdoublee_Gmag[0.0002/0.2] Error on Gmagmagstat.error;phot.magdoubleRPmag[-0.16/1.61] RP-band magnitudemagphot.mag;em.opt.Rdoublee_RPmag[0.0006/0.4] Error on RPmagmagstat.error;phot.magdoublepmRA[-60.6/-17.2]? Proper motion in right ascensionmas/yrpos.pm;pos.eq.rafloatnullablee_pmRA[0.04/1.7]? Error in pmRAmas/yrstat.error;pos.pm;pos.eq.rafloatnullablepmDE[-20.3/20.4]? Proper motion in declinationmas/yrpos.pm;pos.eq.decfloatnullablee_pmDE[0.03/1.4]? Error in pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatnullableRVel[2.7/20.9]? Radial Velocitykm/sphys.veloc;pos.heliocentricfloatnullablee_RVel[0.2/7]? Error on RVelkm/sstat.error;spect.dopplerVelocfloatnullableRUWE[0.87/38.3]? Re-normalised unit weight errorstat.weightfloatnullablef_RUWE[+] Flag on RUWE (2)meta.codecharr_RVelReferences used for RVel (3)meta.ref;pos.framechar_RA.icrsRight ascension (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) at Epoch=J2000, proper motions taken into accountdegpos.eq.decnullableindexedJ/AJ/161/87/table3Final {epsilon}Cha association membership listrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar identifiermeta.id;meta.maincharf_Name[*] Flag on Name (1)meta.codecharSpTSpectral Typesrc.spTypecharDist[93.04/115.7]? Distance (2)pcpos.distance;src.orbitalfloatnullablee_Dist[0.2/3.4]? Negative error on Distpcstat.errorfloatnullableE_Dist[0.2/3.7]? Positive error on Distpcstat.error;stat.maxfloatnullableBPmag[4.86/18.84]? Gaia BP magnitudemagphot.mag;em.opt.BfloatnullableGmag[4.78/17.12]? G-band magnitudemagphot.mag;em.optfloatnullableRPmag[4.93/15.95]? Gaia RP magnitudemagphot.mag;em.opt.Rfloatnullablef_JmagLimit flag on Jmagmeta.codecharJmag[5.02/14.36]? 2MASS J-band magnitudemagphot.mag;em.IR.Jfloatnullablef_HmagLimit flag on Hmagmeta.codecharHmag[5.04/13.38]? 2MASS H-band magnitudemagphot.mag;em.IR.HfloatnullableKmag[4.59/12.81]? 2MASS K-band magnitudemagphot.mag;em.IR.KfloatnullableMultMultiplicity code (3)meta.code.multipcharDisk?IR excess and/or other evidence indicative of presence of circumstellar diskmeta.codecharJ/AJ/161/87/table4Provisional {epsilon}Cha association membership listSpTSpectral types determinedsrc.spTypecharRPmag[6.6/18.19] Gaia RP magnitudemagphot.mag;em.opt.Rfloatf_JmagLimit flag on Jmagmeta.codecharJmag[6.35/15.85] 2MASS J-band magnitudemagphot.mag;em.IR.Jfloatf_HmagLimit flag on Hmagmeta.codecharHmag[6.23/15.03] 2 MASS H-band magnitudemagphot.mag;em.IR.Hfloatf_KmagLimit flag on Kmagmeta.codecharKmag[6.17/12.64] 2MASS K-band magnitudemagphot.mag;em.IR.KfloatMultMultiplicity code (2)meta.code.multipcharDisk?IR excess and/or other evidence indicative of presence of circumstellar diskmeta.codecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar identifiermeta.id;meta.maincharDist[85.17/105.3] Distance (1)pcpos.distance;src.orbitalfloate_Dist[0.24/6.11] Negative error on Distpcstat.errorfloatE_Dist[0.25/7.14] Positive error on Distpcstat.error;stat.maxfloatBPmag[6.93/20.48] Gaia BP magnitudemagphot.mag;em.opt.BfloatGmag[6.79/19.93] G-band magnitudemagphot.mag;em.optfloat