J/AJ/147/146ivo://CDS.VizieR/J/AJ/147/146doi:10.26093/cds/vizier.51470146CDSKraus A.L.Shkolnik E.L.Allers K.N.Liu M.C.2017-06-12T08:24:42Z2015-01-21T14:32:46ZCDS support team

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

cds-question@unistra.frstellar-associationslate-type-starsm-starsstellar-spectral-typesspectroscopyline-intensitiesproper-motionsWe report the selection and spectroscopic confirmation of 129 new late-type (SpT=K3-M6) members of the Tucana-Horologium moving group, a nearby (d~40pc), young ({tau}~40Myr) population of comoving stars. We also report observations for 13 of the 17 known Tuc-Hor members in this spectral type range, and that 62 additional candidates are likely to be unassociated field stars; the confirmation frequency for new candidates is therefore 129/191=67%. We have used radial velocities, H{alpha} emission, and Li_6708_ absorption to distinguish between contaminants and bona fide members. Our expanded census of Tuc-Hor increases the known population by a factor of ~3 in total and by a factor of ~8 for members with SpT>=K3, but even so, the K-M dwarf population of Tuc-Hor is still markedly incomplete. Our expanded census allows for a much more detailed study of Tuc-Hor than was previously feasible. The spatial distribution of members appears to trace a two-dimensional sheet, with a broad distribution in X and Y, but a very narrow distribution (+/-5pc) in Z. The corresponding velocity distribution is very small, with a scatter of +/-1.1km/s about the mean UVW velocity for stars spanning the entire 50pc extent of Tuc-Hor. We also show that the isochronal age ({tau}~20-30Myr) and the lithium depletion boundary age ({tau}~40Myr) disagree, following the trend in other pre-main-sequence populations for isochrones to yield systematically younger ages. The H{alpha} emission line strength follows a trend of increasing equivalent width with later spectral type, as is seen for young clusters. We find that moving group members have been depleted of measurable lithium for spectral types of K7.0-M4.5. None of our targets have significant infrared excesses in the WISE W3 band, yielding an upper limit on warm debris disks of F<0.7%. Finally, our purely kinematic and color-magnitude selection procedure allows us to test the efficiency and completeness for activity-based selection of young stars. We find that 60% of K-M dwarfs in Tuc-Hor do not have ROSAT counterparts and would have been omitted in X-ray-selected samples. In contrast, GALEX UV-selected samples using a previously suggested criterion for youth achieve completeness of 77% and purity of 78%, and we suggest new SpT-dependent selection criteria that will yield >95% completeness for {tau}~40Myr populations with GALEX data available.2014AJ....147..146Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/147/146CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/denis : The DENIS database (DENIS Consortium, 2005)I/322 : UCAC4 Catalogue (Zacharias+, 2012)V/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)I/284 : The USNO-B1.0 Catalog (Monet+ 2003)J/ApJ/762/88 : Young stellar kinematic group candidate members (Malo+, 2013)J/ApJ/753/147 : Herschel observations stars in THA (Donaldson+, 2012)J/ApJ/758/56 : Young M dwarfs within 25pc. II. Kinematics (Shkolnik+, 2012)J/ApJ/699/649 : Young M dwarfs within 25pc. I. (Shkolnik+, 2009)J/AJ/134/2340 : Membership of Praesepe & Coma Berenices clusters (Kraus+, 2007)J/AJ/132/866 : New M dwarfs in solar neighborhood (Riaz+, 2006)J/A+A/460/695 : Search for Associations Containing Young stars (Torres+, 2006)J/AJ/128/463 : A preliminary 20pc census from the NLTT catalogue (Reid+, 2004)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/147/146https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/147/146http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/147/146https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/147/146https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/147/146http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/147/146GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/147/146/stars (Selection criteria , and spectroscopy of candidate Tuc-Hor members)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/147/146/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/147/146/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/147/146/stars?GETtext/xml+votable180.050000true40.4470833-52.99183330.0055555555555555566/16455 16719 17231 17394 17502 17606 18760 22535 32868 32909 32912 32917 32923 32930 32937 32970 33006 33065 33129 33170 33186 33329 33342 33349 33351 33355 33367 33370 33382 33422 33429 33446 33456 33461 33464 33468 33482 33493 33500 33501 33512 33513 33517 33520 33523 33529 33545 33551 33556 33557 33583 33593 33594 33643 33659 33665 33666 33670 33677 33689 33694 33695 33697 33706 33718 33725 33737 33756 33919 33956 33965 33993 33996 34012 34041 34058 34127 34167 34208 34259 34293 34312 34380 34415 34450 34486 34530 34577 34611 34699 34733 34819 34823 34829 34830 34834 34836 34840 34843 34849 34857 34859 34880 34885 34896 34916 34920 34939 34959 34963 35002 35027 35037 35042 35047 35123 35131 35147 35171 35268 35380 35391 35394 35415 35531 35776 35845 35847 35859 35861 35885 35887 35908 35945 35992 36032 36308 36778 45073 45120 45121 45150 45168 45319 45324 45336 45345 45378 45389 45394 45416 45471 45472 45492 45503 45510 45544 45852 45876 45894 45918 45927 45962 45967 45970 45977 45986 45987 46064 46082 46087 46115 46188 46197 46201 46207 46226 46302 46339 46350 46601 46623 46668 46692 46739 46744 46754 46758 47462 47466 48163 486917.952274030004205e-20 1.0188844282367877e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/147/146?format=asciiOpticaldefaultJ/AJ/147/146/starsSelection criteria , and spectroscopy of candidate Tuc-Hor membersNameCommon star namemeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSt"Known" or "Candidate" member statusmeta.code.memberchar2MASS2MASS identifier of the known or candidate Tuc-Hor member (HHMMSSss+DDMMSSs, J2000)meta.id;meta.maincharRmag[6.4/16.3] R-band magnitude from USNO-B1.0 survey (Monet et al. 2003, I/284) (1)magphot.mag;em.opt.RfloatnullableKmag[4.19/11.28] Ks band magnitude (1)magphot.mag;em.IR.KfloatnullablepmRA? Proper motion in Right Ascension ({mu}) (2)mas/yrpos.pm;pos.eq.rafloatnullablepmDE? Proper motion in Declination ({mu}) (2)mas/yrpos.pm;pos.eq.decfloatnullablee_pmDE? Uncertainty in proper motionmas/yrstat.error;pos.pm;pos.eq.decfloatnullableSpT1Spectral type from SED-fit SpT_SED_ (3)src.spTypechare_SpT1Error in SpT1stat.errorfloatnullablembol[6.44/14.09] Apparent bolometric magnitude (3)magphot.mag.bolfloatnullablee_mbolError in mbolmagstat.errorfloatnullableDMph[-0.37/4.4] Photometric distance modulus (3)magphot.mag.distModfloatnullablee_DMphError in DMphmagstat.errorfloatnullablepmO-C? Proper motion residual {Delta}{mu} (5)mas/yrstat.fit.residualfloatnullableDMkin? Best-fit kinematic distance modulusmagphot.mag.distModfloatnullableDateUT date for our MIKE observations (6)time.epochnullableExp[5/720] Exposure time (t_int_)stime.duration;obs.exposureintnullableS/NSignal/Noise ratio for each spectrum at 6600{AA}stat.snrintnullableRVRadial velocity (v_rad_) (7)km/sphys.veloc;pos.heliocentricfloate_RVError in RVkm/sstat.errorfloatRVO-CRadial velocity discrepancy ({Delta}v_rad_) (8)km/sstat.fit.residualfloatvsiniRotational velocitykm/sphys.veloc.rotatfloate_vsiniError in vsinikm/sstat.error;phys.veloc.rotatfloatSpTMK spectral type (9)src.spTypecharEWHaH{alpha} equivalent width (in {AA}) (10)0.1nmspect.line.eqWidth;em.line.HalphafloatEWLiLi{lambda}6708{AA} equivalent width in m{AA} (10)0.1pmspect.line.eqWidthfloatMmRV[YN] Assessment of an object's membership in Tuc-Hor based on radial velocity (11)meta.code.membercharMmHa[?YN] Assessment of an object's membership in Tuc-Hor based on the presence (or absence) of lithium (11)meta.code.membercharMmLi[?YN] Assessment of an object's membership in Tuc-Hor based on H{alpha} emission (11)meta.code.membercharMm[YN] Final assessment of an object's membership in Tuc-Hor (11)meta.code.membercharu_Mm[?] Uncertainty flag on Mmmeta.code.errorcharn_MmCriterion used for making that judgement (RV, H{alpha}, or Li) (11)meta.notef_Mm[a12] "a" indicates a possible field interloper (see caption of Figure 12), "2" or "3" for spectroscopic binaries (in tables 3 and 4 resp.)meta.codecharOptDisplay the data from the optical catalogs USNO-B1.0 (Monet et al. 2003, I/284) and UCAC4 (Zacharias et al. 2012, I/322)meta.ref.urlintnullableDenisDisplay the data from the DENIS databasemeta.ref.urlintnullable_RAPositions derived from 2MASS designations (right ascension part)degpos.eq.ra;meta.main_DEPositions derived from 2MASS designations (declination part)degpos.eq.dec;meta.main