J/ApJ/825/91ivo://CDS.VizieR/J/ApJ/825/91doi:10.26093/cds/vizier.18250091CDSLewis J.A.Lada C.J.2017-12-05T05:10:21Z2016-10-11T14:36:54ZCDS support team

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

cds-question@unistra.fryoung-stellar-objectsmolecular-cloudsextinctionIn the list of young stellar objects (YSOs) compiled by Megeath et al. (2012, J/AJ/144/192) for the Orion A molecular cloud, only 44 out of 1208 sources found projected onto low extinction (A_K_<0.8mag) gas are identified as protostars. These objects are puzzling because protostars are not typically expected to be associated with extended low extinction material. Here, we use high resolution extinction maps generated from Herschel data, optical/infrared and Spitzer Space Telescope photometry and spectroscopy of the low extinction protostellar candidate sources to determine if they are likely true protostellar sources or contaminants. Out of 44 candidate objects, we determine that 10 sources are likely protostars, with the rest being more evolved YSOs (18), galaxies (4), false detections of nebulosity and cloud edges (9), or real sources for which more data are required to ascertain their nature (3). We find none of the confirmed protostars to be associated with recognizable dense cores and we briefly discuss possible origins for these orphaned objects.2016ApJ...825...91Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/825/91CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toV/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)J/ApJS/224/5 : Herschel Orion Protostar Survey (HOPS): SEDs (Furlan+, 2016)J/A+A/589/A80 : APOGEE strings (Hacar+, 2016)J/A+A/566/A45 : Orion optical-depth and column-density maps (Lombardi+, 2014)J/ApJ/786/29 : Catalog of distances to molecular clouds (Schlafly+, 2014)J/ApJS/207/5 : YSOs in LDN 1641 with Hectochelle spectra (Fang+, 2013)J/AJ/144/192 : Spitzer survey of Orion A & B. I. YSO catalog (Megeath+, 2012)J/ApJ/752/59 : Low-mass population in L1641 (Hsu+, 2012)J/ApJ/723/1019 : Galactic SFR and gas surface densities (Heiderman+, 2010)J/A+A/504/461 : YSOs in L1630N and L1641 (Fang+, 2009)J/A+A/498/167 : Embedded sources in L 1688 (van Kempen+, 2009)J/A+A/496/153 : Molecular hydrogen flows along Ori A cloud (Davis+, 2009)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/825/91https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/825/91http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/825/91https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/825/91https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/825/91http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/825/91GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/825/91/table1 (Low Ak source classification)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/825/91/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/825/91/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/825/91/table1?GETtext/xml+votable180.050000true85.5036789-9.42097110.0055555555555555566/21402 21425 21428 21430 21433 21436 21438 21439 22804 22805 22848https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/825/91?format=asciidefaultJ/ApJ/825/91/table1Low Ak source classificationrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[MGM2012][122/2748] Candidate protostar number in Megeath et al. (2012, J/AJ/144/192)meta.id;meta.mainintAk[0.08/0.8] K band extinctionmagphys.absorptionfloate_Ak[0.01/0.06] Uncertainty in Akmagstat.errorfloatSiSi featuremeta.notecharClassClassification from this paper (1)src.classcharNotesNotesmeta.notecharHOPS[25/382]? Herschel Orion Protostar Survey IDmeta.id.crossintnullableHClassHerschel Orion Protostar Survey classification (2)src.classcharRefReference(s) (3)meta.ref;pos.framecharSimbadSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.main