J/MNRAS/543/420ivo://CDS.VizieR/J/MNRAS/543/420doi:10.26093/cds/vizier/bg-gz-d4CDSLopez-Valdivia R.Adame L.Roman-Zuniga C.G.Hernandez J.Sanchez E.,Herrnandez-Aburto I.Fernandez-Trincado J.G.Zagala Lagunas E.Carigi L.,Mendez-Delgado J.E.Kounkel M.Serna J.Lane R.R.Stassun K.G.,Villanova S.Kim J.S.Wolk S.J.Stringfellow G.S.Tan J.C.,Roman-Lopes A.Rojas-Ayala B.Pandey R.2026-08-03T07:33:39Z2025-10-13T11:22:30ZCDS support team

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

cds-question@unistra.fryoung-stellar-objectsprotostarschemical-abundancesWe derive atmospheric parameters and chemical abundances in young G-, K-, and M-type stars (temperatures between 6500 and 3100K) using infrared APOGEE-2 spectra. Atmospheric parameters were determined for 548 young stars in the Orion complex (Orion A, B, OB1, and {lambda} Ori) using the TONALLI code. For 340 slow rotators (vsini<=30km/s, we derived C, Mg, Si, K, Ti, and Fe abundances using 19 atomic lines, MARCS model atmospheres, and BACCHUS. To mitigate the impact of circumstellar material, we excluded stars with infrared excess identified via 2MASS and WISE photometry. We find sub-solar [X/H] abundance ratios, consistent across elements and among all four groups, suggesting a chemically homogeneous Orion complex. We computed {alpha}/Fe] from [Mg/Fe], [Si/Fe], and [Ti/Fe], obtaining a median of -0.14+/-0.04, about 0.10dex lower than the value for nearby main-sequence stars (-0.04+/-0.04) at similar [Fe/H]. This result aligns with predictions from Galactic chemical evolution models. Furthermore, the median [C/H] abundance we derived for Orion agrees with previous estimations based on the analysis of the ionized gas of the Orion nebula. This work sets the stage for extending the analysis to stars with circumstellar material and higher rotational velocities, which will not only improve our understanding of Orion, but also provide critical insight into the formation and evolution of young stars, as well as the chemical evolution of the Milky Way.2025MNRAS.543..420Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/543/420CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/543/420https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/543/420http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/543/420https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/543/420https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/543/420http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/543/420GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/543/420/table2 (Atmospheric parameters for 548 G, K, and M pre-main-sequence stars of Orion)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/543/420/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/543/420/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/543/420/table2?GETtext/xml+votable180.050000true79.660004-2.14180.0055555555555555565/5709 5715 5720-5721 5723 5726 5748 5926 5934 6/21402-21403 21425 21427-21428 21430 21433 21435-21436 21438-21439 22804-22805 22807 22814-22815 22845 22848 22851 22854 22857-22859 22867 22873-22877 22888-22889 22891 22899 22981 23695 23698 23717 23719 23724-23725 23727-23728 23730https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/543/420?format=asciidefaultJ/MNRAS/543/420/table2Atmospheric parameters for 548 G, K, and M pre-main-sequence stars of OrionrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintName2MASS identification number, 2MHHMMSSss+DDMMSSsmeta.id;meta.maincharRAJ2000Right Ascencion (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainTeff25Effective temperature at percentile 25Kphys.temperature.effectivefloatTeff50Effective temperature at percentile 50Kphys.temperature.effectivefloatTeff75Effective temperature at percentile 75Kphys.temperature.effectivefloatlogg25Surface gravity at percentile 25log(cm.s**-2)phys.gravityfloatlogg50Surface gravity at percentile 50log(cm.s**-2)phys.gravityfloatlogg75Surface gravity at percentile 75log(cm.s**-2)phys.gravityfloat[M/H]25Overall metallicity at percentile 25phys.abund.Zfloat[M/H]50Overall metallicity at percentile 50phys.abund.Zfloat[M/H]75Overall metallicity at percentile 75phys.abund.Zfloatalpha25alpha elements abundance at percentile 25phys.abundfloatalpha50alpha elements abundance at percentile 50phys.abundfloatalpha75alpha elements abundance at percentile 75phys.abundfloatv25Projected rotational velocity at percentile 25km/sphys.veloc.rotatfloatv50Projected rotational velocity at percentile 50km/sphys.veloc.rotatfloatv75Projected rotational velocity at percentile 75km/sphys.veloc.rotatfloat[C/H]? Mean [C/H] abundancephys.abundfloatnullablee_[C/H]? Lower error on carbon abundancestat.error;phys.abundfloatnullableSimbadSimbad column added by the CDSmeta.ref.urlcharE_[C/H]? Upper error on carbon abundancestat.error;stat.maxfloatnullableo_[C/H]? Number of lines used in carbon abundance determinationmeta.numberfloatnullable[Mg/H]? Mean [Mg/H] abundancephys.abundfloatnullablee_[Mg/H]? Lower error on magnesium abundancestat.error;phys.abundfloatnullableE_[Mg/H]? Upper error on magnesium abundancestat.error;stat.maxfloatnullableo_[Mg/H]? Lines used in magnesium abundance determinationmeta.numberfloatnullable[Si/H]? Mean [Si/H] abundancephys.abundfloatnullablee_[Si/H]? Lower error on silicon abundancestat.error;phys.abundfloatnullableE_[Si/H]? Upper error on silicon abundancestat.error;stat.maxfloatnullableo_[Si/H]? Lines used in silicon abundance determinationmeta.numberfloatnullable[K/H]? Mean [K/H] abundancephys.abundfloatnullablee_[K/H]? Lower error on potassium abundancestat.error;phys.abundfloatnullableE_[K/H]? Upper error on potassium abundancestat.error;stat.maxfloatnullableo_[K/H]? Lines used in potassium abundance determinationmeta.numberfloatnullable[Ti/H]? Mean [Ti/H] abundancephys.abundfloatnullablee_[Ti/H]? Lower error in titanium abundancestat.error;phys.abundfloatnullableE_[Ti/H]? Upper error in titanium abundancestat.error;stat.maxfloatnullableo_[Ti/H]? Lines used in titanium abundance determinationmeta.numberfloatnullable[Fe/H]? Mean [Fe/H] abundancephys.abund.Fe;stat.meanfloatnullablee_[Fe/H]? Lower error in iron abundancestat.error;phys.abund.FefloatnullableE_[Fe/H]? Upper error in iron abundancestat.error;stat.maxfloatnullableo_[Fe/H]? Lines used in iron abundance determinationmeta.numberfloatnullablevmic? Microturbulence velocitykm/sphys.veloc.microTurbfloatnullable[alpha/Fe]? alpha-elements to iron abundance ratiophys.abundfloatnullablee_[alpha/Fe]? Error in alpha-elements to iron abundancestat.error;phys.abundfloatnullable