J/ApJ/540/236ivo://CDS.VizieR/J/ApJ/540/236doi:10.26093/cds/vizier.15400236CDSHillenbrand L.A.Carpenter J.M.2005-05-24T21:04:56Z2005-05-24T21:04:51ZCDS support team

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

cds-question@unistra.fropen-star-clustersinfrared-photometryWe present the results of a 0.5"-0.9" FWHM imaging survey at K (2.2{mu}m) and H (1.6{mu}m) covering ~ 5.1'x5.1' centered on {theta}^1^C Ori, the most massive star in the Orion Nebula Cluster (ONC). At the age and distance of this cluster, and in the absence of extinction, the hydrogen-burning limit (0.08M_{sun}_) occurs at K~13.5mag, while an object of mass 0.02M_{sun}_ has K~16.2mag. Our photometry is complete for source detection at the 7{sigma} level to K~17.5mag and thus is sensitive to objects as low-mass as 0.02M_{sun}_ seen through visual extinction values as high as 10mag. We use the observed magnitudes, colors, and star counts to constrain the shape of the inner ONC stellar mass function across the hydrogen-burning limit. After determining the stellar age and near-infrared excess properties of the optically visible stars in this same inner ONC region, we present a new technique that incorporates these distributions when extracting the mass function from the observed density of stars in the K-(H-K) diagram. We find that our data are inconsistent with a mass function that rises across the stellar/substellar boundary. Instead, we find that the most likely form of the inner ONC mass function is one that rises to a peak around 0.15M_{sun}_, and then declines across the hydrogen-burning limit with slope N(log M){prop.to}M^0.57^. We emphasize that our conclusions apply to the inner 0.71pc x 0.71pc of the ONC only; they may not apply to the ONC as a whole where some evidence for general mass segregation has been found.2000ApJ...540..236Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/540/236CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/540/236https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/540/236http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/540/236https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/540/236https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/540/236http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/540/236GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/540/236/table1 (Keck/NIRC photometry and astrometry for the inner ONC)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/540/236/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/540/236/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/540/236/table1?GETtext/xml+votable180.050000true83.780875-5.43005560.0055555555555555566/21439https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/540/236?format=asciiInfrareddefaultJ/ApJ/540/236/table1Keck/NIRC photometry and astrometry for the inner ONCl_KmagLimit on KmagcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[HC2000]Orion Nebula Cluster Identification number (1)intRAJ2000Right Ascension (J2000) (2)pos.eq.ra;meta.mainDEJ2000Declination (J2000) (2)pos.eq.dec;meta.mainKmag? The 2.2{mu}m magnitude from Keck/NIRCmagfloatnullablel_HmagLimit on HmagcharHmag? The 1.6{mu}m magnitude from Keck/NIRCmagfloatnullablee_Kmag? IRAF/PHOT errors in Kmag; intended for relative comparison onlymagfloatnullablee_Hmag? IRAF/PHOT errors in Hmag; intended for relative comparison onlymagfloatnullableOptIDOptical identification (3)charAltIDAlternative IR identification (4)char