J/ApJ/705/1416ivo://CDS.VizieR/J/ApJ/705/1416doi:10.26093/cds/vizier.17051416CDSReiners A.Basri G.2017-12-05T05:11:00Z2012-01-03T15:00:39ZCDS support team

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

cds-question@unistra.frm-starsradial-velocitydwarf-starsstellar-distanceIn a volume-limited sample of 63 ultracool dwarfs of spectral type M7-M9.5, we have obtained high-resolution spectroscopy with UVES at the Very Large Telescope and HIRES at Keck Observatory. In this first paper we introduce our volume-complete sample from DENIS and 2MASS targets, and we derive radial velocities and space motion. Kinematics of our sample are consistent with the stars being predominantly members of the young disk. The kinematic age of the sample is 3.1Gyr. We find that six of our targets show strong Li lines implying that they are brown dwarfs younger than several hundred million years. Five of the young brown dwarfs were unrecognized before. Comparing the fraction of Li detections to later spectral types, we see a hint of an unexpected local maximum of this fraction at spectral type M9. It is not yet clear whether this maximum is due to insufficient statistics, or to a combination of physical effects including spectral appearance of young brown dwarfs, Li line formation, and the star formation rate at low masses.2009ApJ...705.1416Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/705/1416CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/denis : The DENIS database (DENIS Consortium, 2005)II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)J/MNRAS/404/1817 : 2MASS/SDSS data for 806 ultracool dwarfs (Zhang+, 2010)J/AJ/137/1 : Proper motions and astrometry of late-type dwarfs (Faherty+,J/MNRAS/394/857 : UKIDSS-2MASS proper motion survey (Deacon+, 2009)J/AJ/136/1290 : Ultracool dwarfs from the 2MASS (Reid+, 2008)J/AJ/133/439 : Luminosity function of M7-L8 ultracool dwarfs (Cruz+, 2007)J/A+A/446/515 : Distances of nearby ultracool dwarfs (Phan-Bao+, 2006)J/A+A/441/653 : 32 DENIS nearby red dwarfs (Crifo+, 2005)J/AJ/126/2421 : 2MASS-Selected sample of ultracool dwarfs (Cruz+, 2003)J/AJ/126/1526 : IR photometry of ultracool dwarfs (Bouy+, 2003)J/A+A/401/959 : 35 DENIS late-M dwarfs between 10 and 30pc (Phan-Bao+, 2003)J/A+A/380/590 : 30 DENIS late-M dwarfs between 15 and 30pc (Phan-Bao+, 2001)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/705/1416https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/705/1416http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/705/1416https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/705/1416https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/705/1416http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/705/1416GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/705/1416/table1 (Sample targets and their space motion)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/705/1416/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/705/1416/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/705/1416/table1?GETtext/xml+votable180.050000true4.859420846.23550280.0055555555555555566/399 2784 2978 4436 4739 4768 4813 5264 5429 8381 9779 10332 10676 10753 10850 11336 11639 11856 13559 14858 14910 16502 16568 16609 17303 17985 18060 18726 19680 19895 20713 22535 22687 22739 22950 23144 24824 24897 25156 25310 25411 25818 26699 33334 33655 34289 34535 34622 34961 35685 35864 35923 36640 38322 40313 40941 44226 44456 44518 44603 45175 48462 490361.5062136169708525e-19 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/705/1416?format=asciiOpticaldefaultJ/ApJ/705/1416/table1Sample targets and their space motionrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintName2MASS-I name (JHHMMSSs+DDMMSSA) (Cat. II/241)meta.id;meta.maincharONameOther namemeta.idcharSpTMK spectral typesrc.spTypecharJmagApparent 2MASS J-band magnitudemagphot.mag;em.IR.JfloatDistSpectrophotometric distance (1)pcpos.distance;pos.heliocentricfloatr_Dist[a-f] Distance reference (2)meta.ref;pos.framecharUVelocity component Ukm/sphys.veloc;pos.cartesian.xintVVelocity component Vkm/sphys.veloc;pos.cartesian.yintWVelocity component Wkm/sphys.veloc;pos.cartesian.zintVradRadial velocity (V_rad_) (3)km/sspect.dopplerVeloc;pos.heliocentricfloatr_Vrad? Vrad reference (4)meta.ref;pos.frameintnullableNoteNote about binarity and Li presence (5)meta.notechar2MASSActual 2MASS identification (from 2MASS-PSC, Cat. II/246)meta.id;meta.mainchar2MDisplay the 2MASS data (Cutri et al. 2003, Cat. II/246)meta.ref.urlcharSimbadSimbad column added by the CDSchar_RAPositions from 2MASS name (right ascension part)degpos.eq.ra;meta.main_DEPositions from 2MASS name (declination part)degpos.eq.dec;meta.main