J/ApJ/805/57ivo://CDS.VizieR/J/ApJ/805/57doi:10.26093/cds/vizier.18050057CDSTottle J.Mohanty S.2017-12-15T10:55:37Z2016-05-04T07:14:00ZCDS support team

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

cds-question@unistra.frstellar-spectral-typeseffective-temperatureextinctionyoung-stellar-objectsastronomical-modelsinfrared-photometryWe test state-of-the-art model atmospheres for young very-low-mass stars and brown dwarfs in the infrared, by comparing the predicted synthetic photometry over 1.2-24{mu}m to the observed photometry of M-type spectral templates in star-forming regions. We find that (1) in both early and late young M types, the model atmospheres imply effective temperatures (Teff) several hundred Kelvin lower than predicted by the standard pre-main sequence (PMS) spectral type-Teff conversion scale (based on theoretical evolutionary models). It is only in the mid-M types that the two temperature estimates agree. (2) The Teff discrepancy in the early M types (corresponding to stellar masses >~0.4M_{sun}_ at ages of a few Myr) probably arises from remaining uncertainties in the treatment of atmospheric convection within the atmospheric models, whereas in the late M types it is likely due to an underestimation of dust opacity. (3) The empirical and model-atmosphere J-band bolometric corrections are both roughly flat, and similar to each other, over the M-type Teff range. Thus the model atmospheres yield reasonably accurate bolometric luminosities (Lbol), but lead to underestimations of mass and age relative to evolutionary expectations (especially in the late M types) due to lower Teff. We demonstrate this for a large sample of young Cha I and Taurus sources. (4) The trends in the atmospheric model J-K_s_ colors, and their deviations from the data, are similar at PMS and main sequence ages, suggesting that the model dust opacity errors we postulate here for young ages also apply at field ages.2015ApJ...805...57Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/805/57CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)J/ApJ/767/95 : Improved parameters of smallest KIC stars (Dressing+, 2013)J/ApJ/731/8 : Multiple star formation in Taurus-Auriga (Kraus+, 2011)J/ApJS/196/4 : New young star candidates in Taurus-Auriga (Rebull+, 2011)J/ApJS/186/259 : Taurus Spitzer survey: new candidate members (Rebull+, 2010)J/ApJS/186/111 : Spitzer observations of Taurus members (Luhman+, 2010)J/ApJ/684/654 : Low-mass members of Chamaeleon I (Luhman+, 2008)J/ApJ/675/1375 : IRAC/MIPS photometry in Cha I (Luhman+, 2008)J/A+A/478/507 : Distances & atmospheric param. of MSU stars (Morales+, 2008)J/ApJS/173/104 : Stellar population in Chamaeleon I (Luhman, 2007)J/A+A/446/485 : New very low-mass members in Taurus (Guieu+, 2006)J/ApJ/645/676 : Spatial distribution of brown dwarfs in Taurus (Luhman+, 2006)J/ApJ/602/816 : Chamaeleon I star-forming region census (Luhman, 2004)J/A+A/416/555 : Brown Dwarfs in ChaI Dark Cloud (Lopez-Marti+ 2004)J/A+A/337/403 : Low-mass stars evolutionary models (Baraffe+ 1998)J/ApJS/101/117 : UBVRIJHKLMNQ photometry in Taurus-Auriga (Kenyon+ 1995)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/805/57https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/805/57http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/805/57https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/805/57https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/805/57http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/805/57GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/805/57/table2 (Properties of the 96 class III Taurus objects)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/805/57/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/805/57/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/805/57/table2?GETtext/xml+votable180.050000true60.955416726.18111110.005555555555555556Cone search capability for table J/ApJ/805/57/table1 (Properties of the 78 class III Cha I objects)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/805/57/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/805/57/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/805/57/table1?GETtext/xml+votable180.050000true163.1539167-74.67463890.0055555555555555566/337 342 350 377 1031 1033 1037 1039 1040 1047 1050 1051 1052 1054 1069 1073 1074 1075 1078 1079 1080 1082 1114 1115 1154 1159 1168 1169 1170 1180 23542 23543 23549 23551 24201 24221 24232 24294 36956 36957 37123 37128 37130 37131 371328.650015785639275e-20 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/805/57?format=asciiOpticalInfrareddefaultJ/ApJ/805/57/table2Properties of the 96 class III Taurus objectsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar name (JHHMMSSss-DDMMSSs)meta.id;meta.maincharf_Name[eh] Flag on Name (1)meta.codecharl_SpT[>=] Limit flag on SpT (2)meta.code.errorcharSpTMK spectral typesrc.spTypecharJmag[8.3/17.9] J-band magnitude from 2MASS unless flaggedmagphot.mag;em.IR.JfloatHmag[7.6/16.8] H-band magnitude from 2MASS unless flaggedmagphot.mag;em.IR.HfloatKmag[7.4/16] K-band magnitude from 2MASS unless flaggedmagphot.mag;em.IR.KfloatAjL[0/7] J-band extinction (A_J,L_) (3)phys.absorptionfloatl_TL[<=] Limit flag on TLmeta.code.errorcharTL[2300/3850] Effective temperature (3)Kphys.temperature.effectiveintLL[0.0003/2.5] Bolometric luminosity (3)solLumphys.luminositydoubleAj[0/7] Atmosphere-fit J-band NIR extinction (A_J,NIR_)phys.absorptionfloatf_Aj[ ,abfg] Flag on Aj (1)meta.codecharl_TA[<=] Limit flag on TAmeta.code.errorcharTA[1925/3550] Atmosphere-fit temperature T_A_Kphys.temperature.effectiveintLA[0.0005/2] Atmosphere-fit bolometric luminositysolLumphys.luminositydoubleTCatDisplay data from Kraus+, 2011, J/ApJ/731/8 and Luhman+, 2010, J/ApJS/186/111, within 1"meta.ref.urlintnullableSimbadSimbad column added by the CDSmeta.ref.urlchar_RAPositions from Names (right ascension part)degpos.eq.ra;meta.main_DEPositions from Names (declination part)degpos.eq.dec;meta.mainJ/ApJ/805/57/table1Properties of the 78 class III Cha I objectsSimbadNameSimbad column added by the CDSmeta.idcharNameStar name (JHHMMSSss-DDMMSSs)meta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintf_Name[eh] Flag on Name (1)meta.codecharl_SpT[>=] Limit flag on SpT (2)meta.code.errorcharSpTMK spectral typesrc.spTypecharJmag[8.3/17.9] J-band magnitude from 2MASS unless flaggedmagphot.mag;em.IR.Jfloatf_Jmag[cd] Flag on Jmag (1)meta.codecharHmag[7.6/16.8] H-band magnitude from 2MASS unless flaggedmagphot.mag;em.IR.Hfloatf_Hmag[cd] Flag on Hmag (1)meta.codecharKmag[7.4/16] K-band magnitude from 2MASS unless flaggedmagphot.mag;em.IR.Kfloatf_Kmag[cd] Flag on Kmag (1)meta.codecharAjL[0/7] J-band extinction (A_J,L_) (3)phys.absorptionfloatl_TL[<=] Limit flag on TLmeta.code.errorcharTL[2300/3850] Effective temperature (3)Kphys.temperature.effectiveintLL[0.0003/2.5] Bolometric luminosity (3)solLumphys.luminositydoubleAj[0/7] Atmosphere-fit J-band NIR extinction (A_J,NIR_)phys.absorptionfloatf_Aj[ ,abfg] Flag on Aj (1)meta.codecharl_TA[<=] Limit flag on TAmeta.code.errorcharTA[1925/3550] Atmosphere-fit temperature T_A_Kphys.temperature.effectiveintLA[0.0005/2] Atmosphere-fit bolometric luminositysolLumphys.luminositydoubleLCatDisplay data within 1" from Luhman+, 2007, J/ApJS/173/104 and 2008, J/ApJ/675/1375 catalogsmeta.ref.urlintnullable_RAPositions from Names (right ascension part)degpos.eq.ra;meta.main_DEPositions from Names (declination part)degpos.eq.dec;meta.main