J/AJ/155/34ivo://CDS.VizieR/J/AJ/155/34doi:10.26093/cds/vizier.51550034CDSCruz K.L.Nunez A.Burgasser A.J.Abrahams E.Rice E.L.Reid I.N.,Looper D.2018-10-22T07:55:41Z2018-09-26T13:51:32ZCDS support team

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

cds-question@unistra.frbrown-dwarfsl-dwarfsstellar-spectral-typesinfrared-photometryDiscrepancies between competing optical and near-infrared (NIR) spectral typing systems for L dwarfs have motivated us to search for a classification scheme that ties the optical and NIR schemes together, and addresses complexities in the spectral morphology. We use new and extant optical and NIR spectra to compile a sample of 171 L dwarfs, including 27 low-gravity {beta} and {gamma} objects, with spectral coverage from 0.6-2.4 {mu}m. We present 155 new low-resolution NIR spectra and 19 new optical spectra. We utilize a method for analyzing NIR spectra that partially removes the broad-band spectral slope and reveals similarities in the absorption features between objects of the same optical spectral type. Using the optical spectra as an anchor, we generate near-infrared spectral average templates for L0-L8, L0-L4{gamma}, and L0-L1{beta} type dwarfs. These templates reveal that NIR spectral morphologies are correlated with the optical types. They also show the range of spectral morphologies spanned by each spectral type. We compare low-gravity and field-gravity templates to provide recommendations on the minimum required observations for credibly classifying low-gravity spectra using low-resolution NIR data. We use the templates to evaluate the existing NIR spectral standards and propose new ones where appropriate. Finally, we build on the work of Kirkpatrick et al. to provide a spectral typing method that is tied to the optical and can be used when only H or K band data are available. The methods we present here provide resolutions to several long-standing issues with classifying L dwarf spectra and could also be the foundation for a spectral classification scheme for cloudy exoplanets.2018AJ....155...34Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/155/34CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)J/AJ/123/2806 : Nearby stars in the NLTT catalogue (Reid+, 2002)J/AJ/123/2822 : Photometry of southern NLTT stars (Reid+, 2002)J/AJ/123/2828 : Spectroscopy of northern NLTT stars (Cruz+, 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/AJ/126/2449 : Nearby ultracool dwarfs in galactic plane (Reid+, 2003)J/AJ/126/3007 : Spectroscopy of faint red NLTT dwarfs (Reid+, 2003)J/AJ/127/3553 : JHK photometry and spectroscopy for L and T dwarfsJ/AJ/128/463 : A preliminary 20pc census from the NLTT catalogueJ/AJ/133/439 : Luminosity function of M7-L8 ultracool dwarfs (Cruz+, 2007)J/AJ/133/2825 : Star beyond the NLTT catalog (Reid+, 2007)J/AJ/136/1290 : Ultracool dwarfs from the 2MASS (Reid+, 2008)J/ApJ/676/1281 : L and T dwarfs in 2MASS/SDSS (Metchev+, 2008)J/MNRAS/383/831 : New DENIS nearby L and late-M dwarfs (Phan-Bao+, 2008)J/AJ/139/1808 : Colors and kinematics of SDSS L dwarfs (Schmidt+, 2010)J/MNRAS/404/1817 : 2MASS/SDSS data for 806 ultracool dwarfs (Zhang+, 2010)J/AJ/147/94 : Solar neighborhood. XXXII. L and M dwarfs (Dieterich+, 2014)J/ApJ/794/143 : New SpeX Observations of M7-L6 Dwarfs (Bardalez+, 2014)J/ApJ/810/158 : M,L,T dwarfs fundamental parameters and SEDsJ/AJ/154/112 : NIR spectroscopy of new L and T dwarf candidateshttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/155/34https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/155/34http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/155/34https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/155/34https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/155/34http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/155/34GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/155/34/table3 (L Dwarfs Included in the Field Gravity Template Sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/155/34/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/155/34/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/155/34/table3?GETtext/xml+votable180.050000true37.564702227.06838060.005555555555555556Cone search capability for table J/AJ/155/34/table1 (New Far-Red Optical Observations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/155/34/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/155/34/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/155/34/table1?GETtext/xml+votable180.050000true8.2326972-44.08493190.005555555555555556Cone search capability for table J/AJ/155/34/table4 (Normal L Dwarfs Excluded from the Field Gravity Template Sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/155/34/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/155/34/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/155/34/table4?GETtext/xml+votable180.050000true2.5004342-20.52006190.005555555555555556Cone search capability for table J/AJ/155/34/table5 (Low-gravity L Dwarfs Included in the Low-gravity Template Sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/155/34/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/155/34/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/155/34/table5?GETtext/xml+votable180.050000true8.2326972-44.08493190.005555555555555556Cone search capability for table J/AJ/155/34/table10 (Near-Infrared IRTF SpeX Prism Spectra of Galaxies)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/155/34/table10?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/155/34/table10?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/155/34/table10?GETtext/xml+votable180.050000true2.789191751.82322220.005555555555555556Cone search capability for table J/AJ/155/34/table2 (New Near-Infrared IRTF SpeX Prism Observations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/155/34/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/155/34/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/155/34/table2?GETtext/xml+votable180.050000true0.300687215.59320670.0055555555555555566/221 322 399 439 445 455 496 544 597 599 672 826 906 2044 2164 2502 2784 2789 2812 2978 3101 3144 4116 4226 4253 4316 4709 4719 4775 4825 5718 5783 5854 5919 6328 6597 6613 6783 7030 7033 7162 7220 7364 7369 7440 7744 8348 8402 8581 8625 8715 8735 8746 8794 8808 9015 9072 9124 9169 9318 9385 9449 9479 9569 9628 9715 10114 10234 10445 10657 10702 10975 11205 11292 11445 11453 11662 11700 12369 12430 12466 12579 12582 12744 13341 13432 13455 13544 13557 13559 13672 13678 13885 14084 14850 14858 14910 15085 16021 16546 16577 16609 16802 16856 16867 17075 17096 17434 17530 17729 17883 17930 17985 18031 18032 18155 18266 18449 18594 18683 18711 18717 18719 18726 18866 18931 19138 19369 19697 19763 19813 19857 19895 20040 20051 20141 20326 20415 20436 20591 20754 20996 21093 21157 21209 21296 21298 21435 21864 22535 22687 22739 22796 22937 22950 23144 23193 23471 23533 24631 24632 25015 25314 25433 25515 25853 25935 26166 26196 26210 26287 26300 27019 27058 27201 27653 28006 28277 28316 28346 29987 30061 30983 31144 31268 31601 31657 31863 31871 32284 32402 32426 32462 32650 33655 33767 34219 34291 34400 34406 34434 34535 34622 34645 34660 34780 35202 35325 35387 35495 35499 35518 35538 35630 35669 35685 35902 35906 35911 35923 35951 36223 36253 36418 36458 36467 36560 36602 36640 36740 36845 38176 39482 39556 39807 40191 40332 40375 40379 40738 40882 40952 43343 43444 43512 43575 43739 43966 44436 44807 44929 44954 45007 46376 46671 46846 46961 47357 48171 48409 48455 48593 48643 48883 48957 48990 491391.5062136169708525e-19 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/155/34?format=asciiInfrareddefaultJ/AJ/155/34/table3L Dwarfs Included in the Field Gravity Template SampleSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameTarget name (2MASS identifier or other name) (1)meta.id;meta.maincharONameOther name (not in Table 4)meta.idcharJmag[11.759/16.789] 2MASS J band magnitudemagphot.mag;em.IR.Jfloate_Jmag[0.019/0.15] Uncertainty in Jmagmagstat.error;phot.mag;em.IR.JfloatJ-Ks[0.912/2.483] 2MASS J-K_s_ color indexmagphot.color;em.IR.J;em.IR.Kfloate_J-Ks[0.029/0.18] Uncertainty in J-Ksmagstat.error;phot.color;em.IR.JfloatSpTypeOptical spectral typesrc.spTypecharn_SpType[bcd] Note on SpType (not in Table 5) (2)meta.notecharr_SpTypeReference for SpTypemeta.ref;pos.framecharBibcode1Bibcode of the reference for SpTypemeta.bib.bibcodecharRefSpeXSpeX Prism referencemeta.bibcharBibcode2Bibcode of the reference for SpeX Prismmeta.bib.bibcodecharRefOther reference(s) (3)meta.ref;pos.framecharBibcode3Bibcode of the other reference(s)meta.bib.bibcodechar2MDisplay the 2MASS data (Cutri et al. 2003, Cat. II/246)meta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.mainnullable_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainnullableJ/AJ/155/34/table1New Far-Red Optical ObservationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFS[1.1/1.9] Figure Set 1 element numbermeta.bib.figfloat2MASS2MASS identifier of optical L dwarf (HHMMSSss+DDMMSSs)meta.id;meta.maincharComp[AB ] Component designationmeta.code.multipcharTelTelescope (Keck I, Clay)meta.id;instr.telcharInstInstrument (LRIS, LDSS-3)meta.id;instrcharDateUT date of observationtime.epoch;obsnullableSpTypeDerived optical spectral typesrc.spTyper_SpTypeReference bibcode for SpTypemeta.ref;pos.framecharSpType1Previous spectral type, no 1src.spTypecharr_SpType1Reference bibcode for SpType1meta.ref;pos.framecharSpType2Previous spectral type, no 2src.spTyper_SpType2Reference bibcode for SpType2meta.ref;pos.framechar2MDisplay the 2MASS data (Cutri et al. 2003, Cat. II/246)meta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/AJ/155/34/table4Normal L Dwarfs Excluded from the Field Gravity Template SampleSimbadNameSimbad column added by the CDSmeta.idcharJmag[11.759/16.789] 2MASS J band magnitudemagphot.mag;em.IR.JfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameTarget name (2MASS identifier or other name) (1)meta.id;meta.maincharONameOther name (not in Table 4)meta.idchare_Jmag[0.019/0.15] Uncertainty in Jmagmagstat.error;phot.mag;em.IR.JfloatJ-Ks[0.912/2.483] 2MASS J-K_s_ color indexmagphot.color;em.IR.J;em.IR.Kfloate_J-Ks[0.029/0.18] Uncertainty in J-Ksmagstat.error;phot.color;em.IR.JfloatSpTypeOptical spectral typesrc.spTypecharn_SpType[bcd] Note on SpType (not in Table 5) (2)meta.notecharr_SpTypeReference for SpTypemeta.ref;pos.framecharBibcode1Bibcode of the reference for SpTypemeta.bib.bibcodecharRefSpeXSpeX Prism referencemeta.bibcharBibcode2Bibcode of the reference for SpeX Prismmeta.bib.bibcodecharRefOther reference(s) (3)meta.ref;pos.framecharBibcode3Bibcode of the other reference(s)meta.bib.bibcodechar2MDisplay the 2MASS data (Cutri et al. 2003, Cat. II/246)meta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.mainnullable_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainnullableJ/AJ/155/34/table5Low-gravity L Dwarfs Included in the Low-gravity Template SampleSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameTarget name (2MASS identifier or other name) (1)meta.id;meta.maincharONameOther name (not in Table 4)meta.idcharJmag[11.759/16.789] 2MASS J band magnitudemagphot.mag;em.IR.Jfloate_Jmag[0.019/0.15] Uncertainty in Jmagmagstat.error;phot.mag;em.IR.JfloatJ-Ks[0.912/2.483] 2MASS J-K_s_ color indexmagphot.color;em.IR.J;em.IR.Kfloate_J-Ks[0.029/0.18] Uncertainty in J-Ksmagstat.error;phot.color;em.IR.JfloatSpTypeOptical spectral typesrc.spTyper_SpTypeReference for SpTypemeta.ref;pos.framecharBibcode1Bibcode of the reference for SpTypemeta.bib.bibcodecharRefSpeXSpeX Prism referencemeta.bibcharBibcode2Bibcode of the reference for SpeX Prismmeta.bib.bibcodecharRefOther reference(s) (3)meta.ref;pos.framecharBibcode3Bibcode of the other reference(s)meta.bib.bibcodechar2MDisplay the 2MASS data (Cutri et al. 2003, Cat. II/246)meta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.mainnullable_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainnullableJ/AJ/155/34/table10Near-Infrared IRTF SpeX Prism Spectra of Galaxies2MASS2MASS identifier of likely galaxy (HHMMSSss+DDMMSSs)meta.id;meta.maincharDateUT date of observationtime.epoch;obsnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFSFigure Set A1 element number (A1.1 to A1.17)meta.bib.figchar2MDisplay the 2MASS data (Cutri et al. 2003, Cat. II/246)meta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/AJ/155/34/table2New Near-Infrared IRTF SpeX Prism ObservationsSimbadNameSimbad column added by the CDSmeta.idcharNameTarget name (2MASS identifier or other name)meta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateUT date of observationtime.epoch;obsnullable2MDisplay the 2MASS data (Cutri et al. 2003, Cat. II/246)meta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.mainnullable_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainnullable