J/MNRAS/434/966ivo://CDS.VizieR/J/MNRAS/434/966doi:10.26093/cds/vizier.74340966CDSSergison D.J.Mayne N.J.Naylor T.Jeffries R.D.Bell C.P.M.2024-08-06T20:16:48Z2014-09-24T12:42:49ZCDS support team

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

cds-question@unistra.fropen-star-clusterspre-main-sequence-starschemical-abundancesWe have used medium-resolution spectra to search for evidence that proto-stellar objects accrete at high rates during their early 'assembly phase'. Models predict that depleted lithium and reduced luminosity in T-Tauri stars are key signatures of 'cold' high-rate accretion occurring early in a star's evolution. We found no evidence in 168 stars in NGC 2264 and the Orion nebula cluster for strong lithium depletion through analysis of veiling-corrected 6708{AA} lithium spectral line strengths. This suggests that 'cold' accretion at high rates (dM/dt>=5x10^-4^M_{sun}_/yr) occurs in the assembly phase of fewer than 0.5 percent of 0.3<=M*<=1.9M_{sun}_ stars. We also find that the dispersion in the strength of the 6708{AA} lithium line might imply an age spread that is similar in magnitude to the apparent age spread implied by the luminosity dispersion seen in colour-magnitude diagrams. Evidence for weak lithium depletion (<10% in equivalent width) that is correlated with luminosity is also apparent, but we are unable to determine whether age spreads or accretion at rates less than 5x10^-4^M_{sun}_/yr are responsible.2013MNRAS.434..966Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/434/966CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/671/605 : NGC 2264 and ONC PMS stars in the infrared (Cieza+, 2007)J/ApJ/648/1090 : Radial velocities of NGC 2264 stars (Furesz+, 2006)J/AJ/127/1117 : Halpha emission-line stars in NGC2264 (Reipurth+, 2004)J/ApJS/208/28 : H{alpha} survey in the ONC (Szegedi-Elek+, 2013)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/434/966https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/434/966http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/434/966https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/434/966https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/434/966http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/434/966GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/434/966/table2 (Summary of derived parameters from this study)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/434/966/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/434/966/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/434/966/table2?GETtext/xml+votable180.050000true83.6187917-5.41607780.0055555555555555566/21438-21439 22804-22805 23637 23639https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/434/966?format=asciiOpticaldefaultJ/MNRAS/434/966/table2Summary of derived parameters from this studyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterCluster name (ONC or NGC2264)meta.id.parentcharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainW(Li)[-0.3/0.9] Lithium equivalent width ({AA})0.1nmspect.line.eqWidthfloate_W(Li)? rms uncertainty on W(Li)0.1nmstat.errorfloatnullableRV[-8/10] Relative radial velocity (1)km/sphys.veloc;arith.difffloate_RV[2.8] rms uncertainty on RVkm/sstat.errorfloatrj[-0.1/4.0] Accretion veilingphys.absorptionfloate_rj[0.0003/0.153] rms uncertainty on rjstat.errorfloatW(Ha)H{alpha} equivalent width (not corrected for veiling)0.1nmspect.line.eqWidth;em.line.Halphadoublee_W(Ha)rms uncertainty on W(Ha)0.1nmstat.errorfloatVHa[52/147] H{alpha} velocitykm/sspect.dopplerVelocfloate_VHa[1/272] rms uncertainty on VHakm/sstat.errorfloatSimbadNameSimbad column added by the CDSmeta.idchar