J/ApJ/689/1295ivo://CDS.VizieR/J/ApJ/689/1295doi:10.26093/cds/vizier.16891295CDSKirkpatrick J.D.Cruz K.L.Barman T.S.Burgasser A.J.Looper D.L.,Tinney C.G.Gelino C.R.Lowrance P.J.Liebert J.Carpenter J.M.,Hillenbrand L.A.Stauffer J.R.2017-12-12T14:45:07Z2011-03-05T17:53:21ZCDS support team

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

cds-question@unistra.frstellar-spectral-typesline-intensitieslate-type-starsinfrared-photometryUsing a large sample of optical spectra of late-type dwarfs, we identify a subset of late-M through L field dwarfs that, because of the presence of low-gravity features in their spectra, are believed to be unusually young. From a combined sample of 303 field L dwarfs, we find observationally that 7.6+/-1.6% are younger than 100Myr. This percentage is in agreement with theoretical predictions once observing biases are taken into account. We find that these young L dwarfs tend to fall in the southern hemisphere (DEC<0{deg}) and may be previously unrecognized, low-mass members of nearby, young associations like Tucana-Horologium, TW Hydrae, {beta} Pictoris, and AB Doradus. We use a homogeneously observed sample of ~150 optical spectra to examine lithium strength as a function of L/T spectral type and further corroborate the trends noted by Kirkpatrick and coworkers. We use our low-gravity spectra to investigate lithium strength as a function of age. The data weakly suggest that for early- to mid-L dwarfs the line strength reaches a maximum for a fewx100Myr, whereas for much older (few Gyr) and much younger (<100Myr) L dwarfs the line is weaker or undetectable.2008ApJ...689.1295Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/689/1295CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)J/A+A/338/1066 : Optical Spectra of DENIS Brown Dwarf Candidate (Tinney+J/ApJ/564/421 : Spectra of T dwarfs. I. (Burgasser+, 2002)J/AJ/123/3409 : SDSS M, L, and T dwarfs (Hawley+, 2002)J/AJ/126/1526 : IR photometry of ultracool dwarfs (Bouy+, 2003)J/AJ/126/2421 : 2MASS-Selected sample of ultracool dwarfs (Cruz+, 2003)J/A+A/401/959 : 35 DENIS late-M dwarfs between 10 and 30pc (Phan-Bao+, 2003)J/AJ/125/3302 : HST binary very low mass stars and brown dwarfs (Gizis+,J/AJ/127/2856 : Brown dwarfs in the 2MASS Survey (Burgasser+, 2004)J/A+A/414/699 : Spectra of southern late-type dwarfs (Cincunegui+, 2004)J/AJ/127/3553 : JHK photometry and spectroscopy for L and T dwarfs (Knapp+,J/AJ/131/2722 : New L and T dwarfs from the SDSS (Chiu+, 2006)J/AJ/133/439 : Luminosity function of M7-L8 ultracool dwarfs (Cruz+, 2007)J/AJ/136/1290 : Ultracool dwarfs from the 2MASS (Reid+, 2008)J/A+A/503/639 : NIR spectral of M-T dwarfs (Testi, 2009)J/A+A/497/619 : New ultra-cool dwarfs from SDSS and 2MASS (Zhang+, 2009)J/MNRAS/404/1817 : 2MASS/SDSS data for 806 ultracool dwarfs (Zhang+, 2010)http://dwarfarchives.org/ : Photometry, spectroscopy and astrometry of M, Lhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/689/1295https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/689/1295http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/689/1295https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/689/1295https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/689/1295http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/689/1295GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/689/1295/table1 (L dwarf candidates sample from 2MASS)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/689/1295/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/689/1295/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/689/1295/table1?GETtext/xml+votable180.050000true3.7322917-48.73808330.005555555555555556Cone search capability for table J/ApJ/689/1295/table4 (Observations of L dwarfs from litterature sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/689/1295/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/689/1295/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/689/1295/table4?GETtext/xml+votable180.050000true79.7498208-28.47701940.005555555555555556Cone search capability for table J/ApJ/689/1295/table5 (Observations of T dwarfs from litterature sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/689/1295/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/689/1295/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/689/1295/table5?GETtext/xml+votable180.050000true63.8314167-9.58519440.005555555555555556Cone search capability for table J/ApJ/689/1295/table6 (*Ultracool field dwarfs (>=M7) with spectroscopic signatures of low gravity (Youth))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/689/1295/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/689/1295/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/689/1295/table6?GETtext/xml+votable180.050000true8.3494208-15.35859440.005555555555555556Cone search capability for table J/ApJ/689/1295/table7 (Log of additional spectroscopic observations for objects shown in Figs. 7-13)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/689/1295/table7?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/689/1295/table7?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/689/1295/table7?GETtext/xml+votable180.050000true8.3494208-15.35859440.005555555555555556Cone search capability for table J/ApJ/689/1295/table8 (Lithium equivalent width measurements for L0, L2, L4, and L6.5 dwarfs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/689/1295/table8?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/689/1295/table8?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/689/1295/table8?GETtext/xml+votable180.050000true14.6772208-6.856650.0055555555555555566/455 474 485 496 734 968 1075 2255 4253 4316 4630 5002 5077 5320 5413 5634 5854 6223 6613 6625 7369 7440 8361 8794 8995 10114 10291 10813 13455 13885 16850 16867 17332 17514 17530 17594 17729 18060 18683 18866 20141 20318 20436 20591 20993 21171 21209 21861 22415 22654 22681 22759 22950 24580 24632 24716 25015 25314 25443 25470 25558 25709 25711 25775 25876 26210 26264 26786 26861 27019 27201 27205 27402 28055 28277 28427 30505 30764 30856 30956 31236 31268 32284 32457 33767 34102 34219 34400 34645 34660 34780 34803 35059 35202 35364 35495 35538 35630 35902 35906 36223 36253 36602 36845 38382 40375 40901 43512 43575 43864 43957 43966 44807 44829 44942 44954 45007 46310 46671 48455 48593 48643 48957 48990 49100 49139 491408.650015785639275e-20 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/689/1295?format=asciiOpticalInfrareddefaultJ/ApJ/689/1295/refsReferencesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference numbermeta.id;meta.mainintprimaryBibCodeBibcodemeta.bib.bibcodecharAutAuthor's namemeta.bib.authorcharComCommentmeta.notecharJ/ApJ/689/1295/table1L dwarf candidates sample from 2MASSrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintS[Ld/OT] Sample (1)meta.idchar2MASS2MASS name (JHHMMSSss+DDMMSSs)meta.id;meta.maincharn_2MASSSimbad column added by the CDSmeta.notecharJmag2MASS J-band magnitudemagphot.mag;em.IR.Jfloate_JmagJmag uncertaintymagstat.error;phot.mag;em.IR.JfloatHmag2MASS H-band magnitudemagphot.mag;em.IR.Hfloate_HmagHmag uncertaintymagstat.error;phot.mag;em.IR.HfloatKsmag2MASS Ks-band magnitudemagphot.mag;em.IR.Kfloate_KsmagKsmag uncertaintymagstat.error;phot.mag;em.IR.KfloatJ-KsJ-Ks color indexmagphot.color;em.IR.J;em.IR.Kfloate_J-KsJ-Ks uncertaintymagstat.error;phot.color;em.IR.JfloatSpTypeMK optical spectral type (for Ld sample)src.spTypecharf_SpType[c] Flag for 2MASS J15394189-0520428 (2)meta.codecharTypeObject type (for OT sample)src.classcharr_Type? Type reference; see refs.dat filemeta.noteintnullableRefDiscovery reference(s); see refs.dat filemeta.ref;pos.framecharONameOther designation(s) or commentmeta.idcharf_OName[b] Flag for 2MASS J14413716-0945590 (3)meta.codechar2MDisplay 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.mainJ/ApJ/689/1295/table3New spectroscopic observations of late-M or L dwarfs from table 1l_CsTLimit flag on CsTmeta.code.errorcharCsTSpectral type from Cs/VOsrc.spTypecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameObject designationmeta.id;meta.maincharf_Name[e] Flag for Gl 337CD (1)meta.codecharRef? Discovery reference (only for table 4); see refs.dat filemeta.ref;pos.frameintnullableObsDateObservation date (UT)time.epoch;obsnullablef_ObsDate[m] for multidates (2)meta.codechartintIntegration timestime.expointCrH-aCrH-a spectral index (3)spect.indexfloatl_CrTLimit flag on CrTmeta.code.errorcharCrTSpectral type from CrHa linesrc.spTypecharRb/TiO? Rb-b/TiO-b spectral index (3)spect.indexfloatnullablel_RbTLimit flag on RbTmeta.code.errorcharRbTSpectral type from Rb/TiOsrc.spTypecharCs/VO? Cs-a/VO-b spectral index (3)spect.indexfloatnullableCol? Color-d spectral index (3)spect.indexfloatnullablel_ColTLimit flag on ColTmeta.code.errorcharColTSpectral type from colsrc.spTypecharl_KI[<~ ] Limit flag on KImeta.code.errorcharKIKI fit spectral typesrc.spTypecharOxOxyde fit spectral typesrc.spTypecharSpTypeFinal optical spectral typesrc.spTypecharf_SpType[b] Flag for 2MASS J00145575-4844171 (4)src.spTypecharDist? Distance (only for table 3)pcpos.distance;pos.heliocentricintnullableu_DistUncertainty flag on Distmeta.code.errorcharf_Dist[p] Dist from trigonometric parallax (5)meta.codecharl_W(Ha)[<= ] Limit flag on W(Ha)meta.code.errorcharW(Ha)H{alpha} equivalent width0.1nmspect.line.eqWidth;em.line.Halphafloatf_W(Ha)[cd] Flag on W(Ha) (6)meta.codecharl_W(Li)[<= ] Limit flag on W(Li)meta.code.errorcharW(Li)LiI equivalent width0.1nmspect.line.eqWidthfloatu_W(Li)Uncertainty flag on W(Li)meta.code.errorcharJ/ApJ/689/1295/table4Observations of L dwarfs from litterature samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameObject designationmeta.id;meta.maincharf_Name[e] Flag for Gl 337CD (1)meta.codecharRef? Discovery reference (only for table 4); see refs.dat filemeta.ref;pos.frameintnullableObsDateObservation date (UT)time.epoch;obsnullablef_ObsDate[m] for multidates (2)meta.codechartintIntegration timestime.expointCrH-aCrH-a spectral index (3)spect.indexfloatl_CrTLimit flag on CrTmeta.code.errorcharCrTSpectral type from CrHa linesrc.spTypecharRb/TiO? Rb-b/TiO-b spectral index (3)spect.indexfloatnullablel_RbTLimit flag on RbTmeta.code.errorcharRbTSpectral type from Rb/TiOsrc.spTypecharCs/VO? Cs-a/VO-b spectral index (3)spect.indexfloatnullablel_CsTLimit flag on CsTmeta.code.errorcharCsTSpectral type from Cs/VOsrc.spTypecharCol? Color-d spectral index (3)spect.indexfloatnullablel_ColTLimit flag on ColTmeta.code.errorcharColTSpectral type from colsrc.spTypecharl_KI[<~ ] Limit flag on KImeta.code.errorcharKIKI fit spectral typesrc.spTypecharOxOxyde fit spectral typesrc.spTypecharSpTypeFinal optical spectral typesrc.spTypecharf_SpType[b] Flag for 2MASS J00145575-4844171 (4)src.spTypecharDist? Distance (only for table 3)pcpos.distance;pos.heliocentricintnullableu_DistUncertainty flag on Distmeta.code.errorcharf_Dist[p] Dist from trigonometric parallax (5)meta.codecharl_W(Ha)[<= ] Limit flag on W(Ha)meta.code.errorcharW(Ha)H{alpha} equivalent width0.1nmspect.line.eqWidth;em.line.Halphafloatf_W(Ha)[cd] Flag on W(Ha) (6)meta.codecharl_W(Li)[<= ] Limit flag on W(Li)meta.code.errorcharW(Li)LiI equivalent width0.1nmspect.line.eqWidthfloatu_W(Li)Uncertainty flag on W(Li)meta.code.errorcharSimbadNameSimbad column added by the CDSmeta.idchar2MDisplay the 2MASS data (Cutri et al. 2003, Cat. II/246)meta.ref.urlchar_RAPositions from Simbad (right ascension part)degpos.eq.ra;meta.main_DEPositions from Simbad (declination part)degpos.eq.dec;meta.mainJ/ApJ/689/1295/table5Observations of T dwarfs from litterature samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameObject designationmeta.id;meta.maincharRefDiscovery reference; see refs.dat filemeta.ref;pos.frameintObsDateObservation date (UT)time.epoch;obsnullablef_ObsDate[m] for multidates (1)meta.codechartintIntegration timestime.expointCsICsI(A) spectral index (2)spect.indexfloatl_CsTLimit flag on CsTmeta.code.errorcharCsTSpectral type from CsIsrc.spTypecharCrH/H2OCrH(A)/H_2_O spectral index (2)spect.indexfloatl_CrTLimit flag on CrTmeta.code.errorcharCrTSpectral type from CrH/H20src.spTypecharFeHFeH(B) spectral type (2)spect.indexfloatu_FeT[~ ] Approximative flag on FeTmeta.code.errorcharFeT? Spectral type from FeHsrc.spTypeintnullableColColor-e spectral index (2)spect.indexfloatl_ColTLimit flag on ColTmeta.code.errorcharColT? Spectral type from Colsrc.spTypeintnullableTypeBy-eye typesrc.spTypecharSpTypeFinal optical spectral typesrc.spTypecharl_W(Ha)Limit flag on W(Ha)meta.code.errorcharW(Ha)? H{alpha} equivalent width0.1nmspect.line.eqWidth;em.line.Halphaintnullablef_W(Ha)[c] Non-significant equivalent widths (3)meta.codecharl_W(Li)Limit flag on W(Li)meta.code.errorcharW(Li)? LiI equivalent width0.1nmspect.line.eqWidthintnullableSimbadNameSimbad column added by the CDSmeta.idchar2MDisplay the 2MASS data (Cutri et al. 2003, Cat. II/246)meta.ref.urlchar_RAPositions from Simbad (right ascension part)degpos.eq.ra;meta.main_DEPositions from Simbad (declination part)degpos.eq.dec;meta.mainJ/ApJ/689/1295/table6*Ultracool field dwarfs (>=M7) with spectroscopic signatures of low gravity (Youth)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameObject namemeta.id;meta.maincharf_Name[d] SSSPM J1102-3431 = 2MASS J11020983-3430355meta.codecharSpTypeOptical spectral typesrc.spTypecharf_SpType[e] Flag for 2MASSI J1615425+495321 (1)src.spTypecharr_SpType? Optical reference; see refs.dat filesrc.spTypeintnullableIRSpTNear-IR spectral typesrc.spTypecharr_IRSpT? Near-IR reference; see refs.dat filesrc.spTypeintnullableJ-Ks? 2MASS J-Ks color indexmagphot.color;em.IR.J;em.IR.Kfloatnullablee_J-Ks? J-Ks uncertaintymagstat.error;phot.color;em.IR.Jfloatnullablef_J-Ks[c] SDSS J102552.43+321234.0 not detected at 2MASS J-bandmeta.codecharRefDiscovery reference; see refs.dat filemeta.ref;pos.frameintRef2Youth reference(s); see refs.dat filemeta.ref;pos.framecharDiagDiagnosticsmeta.notecharSimbadNameSimbad column added by the CDSmeta.idchar2MDisplay the 2MASS data (Cutri et al. 2003, Cat. II/246)meta.ref.urlchar_RAPositions from Simbad (right ascension part)degpos.eq.ra;meta.main_DEPositions from Simbad (declination part)degpos.eq.dec;meta.mainJ/ApJ/689/1295/table7Log of additional spectroscopic observations for objects shown in Figs. 7-13recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameObject namemeta.id;meta.maincharONameOther designationmeta.idcharDateObservation date (UT)time.epoch;obsnullablef_Date[b-e] Multidate (1)meta.codecharTelTelescopemeta.id;instr.telcharf_Tel[f] Flag for Subaru (1)meta.codecharInstInstrumentmeta.id;instrchartintIntegration timestime.expointtint2? Second integration timestime.expointnullabler_SpType? Spectroscopic reference; see refs.dat filesrc.spTypeintnullableSpTypeSpectral typesrc.spTypecharCorTelluric corrected? (3)meta.notecharf_Cor[c] Flag for G 196-3B (1)meta.codecharSimbadNameSimbad column added by the CDSmeta.idchar2MDisplay the 2MASS data (Cutri et al. 2003, Cat. II/246)meta.ref.urlchar_RAPositions from Simbad (right ascension part)degpos.eq.ra;meta.main_DEPositions from Simbad (declination part)degpos.eq.dec;meta.mainJ/ApJ/689/1295/table8Lithium equivalent width measurements for L0, L2, L4, and L6.5 dwarfsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSpTSpectral typesrc.spTypecharNameNamemeta.id;meta.maincharf_Name[a-g] Flag on Name (1)meta.codecharl_W(Li)[<= ] Limit flag on W(Li)meta.code.errorcharW(Li)Lithium equivalent width0.1nmspect.line.eqWidthfloate_W(Li)? W(Li) uncertainty0.1nmstat.errorfloatnullablef_SpT[1-4] Particularity of dwarfs (2)src.spTypeintSimbadNameSimbad column added by the CDSmeta.idchar_RAPositions from Simbad (right ascension part)degpos.eq.ra;meta.main_DEPositions from Simbad (declination part)degpos.eq.dec;meta.main