J/A+A/599/A14ivo://CDS.VizieR/J/A+A/599/A14doi:10.26093/cds/vizier.35990014CDSJoncour I.Duchene G.Moraux E.2017-07-21T10:41:08Z2017-07-03T09:43:52ZCDS support team

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

cds-question@unistra.frmolecular-cloudsmultiple-starsThis work analyses the spatial distribution of stars in Taurus with a specific focus on multiple stars and wide pairs in order to derive new constraints on star formation and early dynamical evolution scenarios. We collected the multiplicity data of stars in Taurus to build an up-to-date stellar/multiplicity catalog. We first present a general study of nearest-neighbor statistics on spatial random distribution, comparing its analytical distribution and moments to those obtained from Monte Carlo samplings. We introduce the one-point correlation {Psi} function to complement the pair correlation function and define the spatial regimes departing from randomness in Taurus. We then perform a set of statistical studies to characterize the binary regime that prevails in Taurus. The {Psi} function in Taurus has a scale-free trend with a similar exponent as the correlation function at small scale. It extends almost 3 decades up to ~60kAU showing a potential extended wide binary regime. This was hidden in the correlation function due to the clustering pattern blending. Distinguishing two stellar populations, single stars versus multiple systems (separation <=1kAU), within Class II/III stars observed at high angular resolution, we highlight a major spatial neighborhood difference between the two populations using nearest-neighbor statistics. The multiple systems are three times more likely to have a distant companion within 10kAU when compared to single stars. We show that this is due to the presence of most probable physical ultra-wide pairs (UWPs, defined as such from their mutual nearest neighbor property), that are themselves generally composed of multiple systems containing up to five stars altogether. More generally, our work highlights; 1) a new large population of candidate UWPs in Taurus within the range 1-60kAU in Taurus and 2) the major local structural role they play up to 60kAU. There are three different types of UWPs; either composed of two tight and comparatively massive stars (MM), by one single and one multiple (SM), or by two distant low-mass singles (SS) stars. These UWPs are biased towards high multiplicity and higher-stellar-mass components at shorter separations. The multiplicity fraction per ultra-wide pair with separation less than 10kAU may be as high as 83.5+/-19.6%. We suggest that these young pre-main sequence UWPs may be pristine imprints of their spatial configuration at birth resulting from a cascade fragmentation scenario of the natal molecular core. They could be the older counterparts, at least for those separated by less than 10kAU, to the <=0.5Myr prestellar cores/Class 0 multiple objects observed at radio/millimeter wavelengths.2017A&A...599A..14Jhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/599/A14CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/135/2496 : Near-IR survey of Class I protostars (Connelley+, 2008)J/ApJS/186/111 : Spitzer observations of Taurus members (Luhman+, 2010)J/ApJS/186/259 : Taurus Spitzer survey: new candidate members (Rebull+, 2010)J/ApJ/731/8 : Multiple star formation in Taurus-Auriga (Kraus+, 2011)J/ApJ/727/64 : Young stellar groups 7 their most massive stars (Kirk+, 2011)J/ApJ/757/141 : Companion IR detection limits in young associationsJ/ApJ/784/126 : Infrared photometry of all known members in TaurusJ/ApJ/799/155 : Sub-stellar companions in Taurus (Daemgen+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/599/A14https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/599/A14http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/599/A14https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/599/A14https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/599/A14http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/599/A14GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/599/A14/tablec1 (*Taurus stars catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/599/A14/tablec1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/599/A14/tablec1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/599/A14/tablec1?GETtext/xml+votable180.050000true60.95526.180.0055555555555555565/270 292 6/325 336-337 342 350 377 1029-1031 1033 1036-1037 1039-1040 1042-1043 1047-1048 1050-1054 1061 1063 1068-1069 1073-1075 1078-1079 1084 1111-1112 1114-1115 1123-1124 1126 1136 1154 1156-1157 1159 1164 1176 1180 23517 23533 23542-23543 23548-23549 23551 24201 24203 24221 24232 24294-24295 24300https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/599/A14?format=asciidefaultJ/A+A/599/A14/refsReferencesComCommentsmeta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference codemeta.notecharBibCodeBibCodemeta.bib.bibcodecharAutAuthor's namemeta.bib.authorcharJ/A+A/599/A14/tablec1*Taurus stars catalogSimbadNameSimbad column added by the CDSmeta.idcharSpTypeSpectral typesrc.spTypecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/338] Sequential numbermeta.recordint2MASS2MASS name (JHHMMSSss+DDMMSSs)meta.idcharNameNamemeta.id;meta.maincharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainMassMass of the primarysolMassphys.massfloatClassClasssrc.classcharNstarsTotal number of stars within 1000AU (spectroscopic binaries not counted as membership)meta.numberintSep1? Separation of companions stars with the primaryarcsecpos.angDistancefloatnullableSep2? Separation of companions stars with the primaryarcsecpos.angDistancefloatnullableSep3? Separation of companions stars with the primaryarcsecpos.angDistancefloatnullableHAR[Y/N] Flag wether the stellar system/star has been observed at High Angular Resolutionmeta.codecharRefReferences papers associated to each star/stellar system, in refs.dat filemeta.id.assoc;pos.framecharJ/A+A/599/A14/tablec2*Catalog of the first nearest neighbor couples of starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/245] Couple sequential numbermeta.id;meta.mainintStarAStar A identification number, as in tablec1.datmeta.idintn_StarA[S ] Note on StarA (1)meta.notecharNameACommon name for star Ameta.idcharNstarsATotal number of stars (2)meta.numberintClassAStar A class (primary star)src.classcharStarBStar B identification number, as in tablec1.datmeta.idintn_StarB[S] Note on StarB (1)meta.notecharNameBCommon name for star Bmeta.idcharNstarsBTotal number of stars (2)meta.numberintClassBStar B classsrc.classchardeltaPSeparation of the two stellar components A and BAUpos.angDistanceintNstarsTotal number of stars as a (hierarchical) couple for the two stellar components A and Bmeta.numberintHAR[-* ] Flag (3)meta.codecharWP[C] C for ultra wide pair candidate since the couple are mutual nearest neighboursmeta.codecharConf[Y] Y for couple has been confirmed as gravitationally bound binaries (4)meta.codechar