J/other/RAA/16.Givo://CDS.VizieR/J/other/RAA/16.G7doi:10.26093/cds/vizier/dx/bgkrhCDSBai Y.Luo A.-L.Comte G.Zhao J.-K.Yang H.-F.Guo Y.-X.Wang Y.-F.,Li Y.-B.Du B.Hou W.Kong X.Yi Z.-P.Song Y.-H.Bai Z.-R.,Zhang J.-N.Wang M.-X.Chen J.-J.Chen X.-Y.Wu K.-F.Zuo F.Wu Y.,Cao Z.-H.Hou Y.-H.Wang Y.-F.Zhang Y.2026-02-10T20:07:19Z2016-11-10T12:27:36ZCDS support team

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

cds-question@unistra.frm-starssubdwarf-starsWe identify 108 M subdwarfs (sdMs) out of more than two hundred thousand M type spectra from the second data release (DR2) of the LAMOST regular survey. This sample, among which 58 members are identified for the first time, includes 33 extreme subdwarfs (esdMs) and 11 ultra subdwarfs (usdMs). The selection is based on the usual ratio of absorption depth of CaH2, CaH3 and TiO5 band systems. We also emphasize the use of the CaH1 band. We provide estimates of spectral subtype (SPT), Lepine metallicity index zeta, effective temperature and [Fe/H]. Both zeta-[Fe/H] and SPT-Teff figures show reasonable consistency; compared to PHOENIX model spectra, average rounded values of [Fe/H] for sdMs, esdMs and usdMs are respectively -0.5, -1 and -1.5. The photometric distances are estimated, indicating that most sources are located within 500pc of the Sun and 350pc of the Galactic disk. Velocities and 3D Galactic motions are also briefly discussed. Among the 108 subdwarfs, seven stars appear to be active with a significant H{alpha} emission line. The source LAMOST J104521.52+482823.3 is a white dwarf - M subdwarf binary, while LAMOST J123045.52+410943.8, also active, exhibits carbon features in red.2016RAA....16..107Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/other/RAA/16.G7CatalogResearchIsServedByTAP VizieR generic servicerelated-toV/146 : LAMOST DR1 catalogs (Luo+, 2015)J/other/RAA/15.1154 : M-giant star candidates in LAMOST DR 1 (Zhong+, 2015)J/other/RAA/15.1182 : M Dwarf catalog of LAMOST DR1 (Guo+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/other/RAA/16.G7https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/other/RAA/16.G7http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/other/RAA/16.G7https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/other/RAA/16.G7https://vizier.iucaa.in/viz-bin/votable?-source=J/other/RAA/16.G7http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/other/RAA/16.G7GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tap1.398457827073138e-19 4.920466254354166e-19defaultJ/other/RAA/16.G7/sampleDerived parameters (table 2), observed magnitudes and adopted extinction (table 3) and distances and velocities (table 5) of the 108 sdMsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLAMOSTLAMOST ID (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharn_LAMOST[*] * indicates objects already known from SDSSmeta.notecharSPTSpectral sub-type (1)meta.notefloatTeffEffective temperatureKphys.temperature.effectiveintzetazeta metallicity index (2)spect.indexfloat[Fe/H]Metallicityphys.abund.ZfloatgmagSDSS g magnitudemagphot.mag;em.opt.BfloatrmagSDSS r magnitudemagphot.mag;em.opt.RfloatimagSDSS i magnitudemagphot.mag;em.opt.Ifloatzmag? SDSS z magnitudemagphot.mag;em.opt.IfloatnullableJmagJohnson J magnitudemagphot.mag;em.IR.JfloatBmag? Johnson B magnitudemagphot.mag;em.opt.BfloatnullableRmag? Cousins R magnitudemagphot.mag;em.opt.RfloatnullableImag? Cousins I magnitudemagphot.mag;em.opt.IfloatnullableVmagJohnson V magnitudemagphot.mag;em.opt.Vfloat3D-ArAdopted extinctionmagphys.absorptionfloatDist? Distance (1)pcpos.distance;pos.heliocentricintnullableZgal? Height above the plane (1)pcpos.cartesian.zintnullablepmRA? Proper motion along RA (1)mas/yrpos.pm;pos.eq.raintnullablepmDE? Proper motion along DE (1)mas/yrpos.pm;pos.eq.decfloatnullableRVP? Pipeline heliocentric radial velocity (1)km/sspect.dopplerVeloc;pos.heliocentricintnullableRVG? Helicoentric radial velocity from Gaussian fitting (1)km/sphys.veloc;pos.heliocentricintnullableVt? Transverse velocity (1)km/sphys.veloc.transverseintnullableUvel? Galactic U velocity (1)km/sphys.veloc;pos.cartesian.xintnullableVvel? Galactic V velocity (1)km/sphys.veloc;pos.cartesian.yintnullableWvel? Galactic W velocity (1)km/sphys.veloc;pos.cartesian.zintnullableVtot? Total velocity (1)km/sphys.velocintnullable