J/AJ/149/158ivo://CDS.VizieR/J/AJ/149/158doi:10.26093/cds/vizier.51490158CDSSchmidt S.J.Hawley S.L.West A.A.Bochanski J.J.Davenport J.R.A.,Ge J.Schneider D.P.2018-01-05T08:55:56Z2015-06-05T08:12:06ZCDS support team

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

cds-question@unistra.frdwarf-starslate-type-starsline-intensitiesstellar-spectral-typesWe present the colors and activity of ultracool (M7-L8) dwarfs from the Tenth Data Release of the Sloan Digital Sky Survey (SDSS). We combine previous samples of SDSS M and L dwarfs with new data obtained from the Baryon Oscillation Sky Survey (BOSS) to produce the BOSS Ultracool Dwarf (BUD) sample of 11820 M7-L8 dwarfs. By combining SDSS data with photometry from 2MASS and the Wide-field Infrared Sky Explorer (WISE) mission, we present ultracool dwarf colors from i-z to W2-W3 as a function of spectral type, and extend the SDSS-2MASS-WISE color locus to include ultracool dwarfs. The i-z, i-J, and z-J colors provide the best indication of spectral type for M7-L3 dwarfs. We also examine ultracool dwarf chromospheric activity through the presence and strength of H{alpha} emission. The fraction of active dwarfs rises through the M spectral sequence until it reaches ~90% at spectral type L0. The fraction of active dwarfs then declines to 50% at spectral type L5; no H{alpha} emission is observed in the late-L dwarfs in the BUD sample. The fraction of active L0-L5 dwarfs is much higher than previously observed. The strength of activity declines with spectral type from M7 through L3, after which the data do not show a clear trend. Using one-dimensional chromosphere models, we explore the range of filling factors and chromospheric temperature structures that are consistent with H{alpha} observations of M0-L7 dwarfs. M dwarf chromospheres have a similar, smoothly varying range of temperature and surface coverage, while L dwarf chromospheres are cooler and have smaller filling factors.2015AJ....149..158Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/149/158CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toV/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)J/AJ/141/97 : SDSS DR7 M dwarfs (West+, 2011)J/AJ/139/1808 : Colors and kinematics of SDSS L dwarfs (Schmidt+, 2010)J/A+A/497/619 : New ultra-cool dwarfs from SDSS and 2MASS (Zhang+, 2009)J/AJ/133/2258 : Activity and kinematics of ultracool dwarfs (Schmidt+, 2007)J/AJ/133/439 : Luminosity function of M7-L8 ultracool dwarfs (Cruz+, 2007)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/149/158https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/149/158http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/149/158https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/149/158https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/149/158http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/149/158GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/149/158/table6 (L dwarf H{alpha} detections and emission strength)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/149/158/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/149/158/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/149/158/table6?GETtext/xml+votable180.050000true1.1451667-40.73494440.0055555555555555566/207 221 222 223 369 439 464 496 544 580 586 734 743 749 763 858 2255 2260 2502 4116 4226 4253 4515 4536 4630 4719 4756 4775 5002 5077 5147 5413 5481 5634 5659 5666 6047 6223 6255 6298 6328 6597 6613 6625 6783 7220 7440 7533 7985 8348 8361 8402 8519 8522 8544 8558 8719 8761 8781 8794 8808 8864 8874 9072 9146 9293 9385 9434 9449 9479 9569 10243 10291 10445 10555 10657 10665 10813 10922 11164 11292 11719 12466 12519 12537 12541 13455 13678 14850 15085 16361 16502 16609 16850 16873 17075 17530 17594 18032 18375 18683 19598 19755 19763 19813 19857 20318 20436 21209 21835 22391 22759 23010 23234 23471 24566 24590 25015 25132 25266 25314 25558 26282 26300 26393 27019 27058 27518 27618 27635 27648 28006 28277 28316 28346 28427 28450 28612 30061 30749 30883 31009 31011 31268 32284 32372 32426 32457 32462 32650 33767 34660 34780 34893 35499 35902 36253 36265 36418 36602 36845 39482 40332 40375 40669 40738 40882 41984 43422 43475 43957 43966 44807 44929 44954 46138 46671 47012 47192 48957 49139https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/149/158?format=asciiOpticaldefaultJ/AJ/149/158/table6L dwarf H{alpha} detections and emission strengthSpTSpectral typesrc.spTypecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint2MASS2MASS designation (HHMMSSss+DDMMSSs, J2000)meta.id;meta.maincharr_EWHa[1/8] Reference for EWHa (1)meta.ref;spect.line.eqWidth;em.line.Halphaintl_EWHa[<] Upper limit flag on EWHameta.code.error;spect.line.eqWidth;em.line.HalphacharEWHa[-1.1/174] H{alpha} equivalent width; in {AA}0.1nmspect.line.eqWidth;em.line.Halphafloatl_logLHa[<] Upper limit flag on logLHameta.code.error;phys.luminosity;em.line.HalphacharlogLHa[-7/-3.6] Log of H{alpha} luminosity ratio to bolometric luminosity, log(L_H{alpha}_/L_bol_)phys.luminosity;em.line.Halpha;spect.linefloatsigHa? Normalized H{alpha} standard deviation {sigma}(H{alpha})/<H_{alpha}_>stat.stdev;em.line.HalphafloatnullableVar[0/20]? Fractional variability (2)src.var;arith.ratiofloatnullableVVariable? (y=yes or n=no)meta.code;src.varcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RAPositions from 2MASS name (right ascension part)degpos.eq.ra;meta.main_DEPositions from 2MASS name (declination part)degpos.eq.dec;meta.main