J/ApJ/813/120ivo://CDS.VizieR/J/ApJ/813/120doi:10.26093/cds/vizier.18130120CDSSmith R.L.Pontoppidan K.M.Young E.D.Morris M.R.2018-01-05T08:55:54Z2016-03-21T15:59:56ZCDS support team

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

cds-question@unistra.fryoung-stellar-objectsinfrared-astronomyspectroscopyThis study reports an unusual heterogeneity in [^12^C^16^O]/[^13^C^16^O] abundance ratios of carbon monoxide observed in the gas phase toward seven ~solar-mass young stellar objects (YSOs) and three dense foreground clouds in the nearby star-forming regions, Ophiuchus, Corona Australis, Orion, and Vela, and an isolated core, L43. Robust isotope ratios were derived using infrared absorption spectroscopy of the 4.7{mu}m fundamental and 2.3{mu}m overtone rovibrational bands of CO at very high spectral resolution ({lambda}/{Delta}{lambda}~95000), observed with the Cryogenic Infrared Echelle Spectrograph (CRIRES) on the Very Large Telescope. We find [^12^C^16^O]/[^13^C^16^O] values ranging from ~85 to 165, significantly higher than those of the local interstellar medium (ISM) (~65-69). These observations are evidence for isotopic heterogeneity in carbon reservoirs in solar-type YSO environments, and encourage the need for refined galactic chemical evolution models to explain the ^12^C/^13^C discrepancy between the solar system and local ISM. The oxygen isotope ratios are consistent with isotopologue-specific photodissociation by CO self-shielding toward the disks, VV CrA N and HL Tau, further substantiating models predicting CO self-shielding on disk surfaces. However, we find that CO self-shielding is an unlikely general explanation for the high [^12^C^16^O]/[^13^C^16^O] ratios observed in this study. Comparison of the solid CO against gas-phase [^12^C^16^O]/[^13^C^16^O] suggests that interactions between CO ice and gas reservoirs need to be further investigated as at least a partial explanation for the unusually high [^12^C^16^O]/[^13^C^16^O] observed.2015ApJ...813..120Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/813/120CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/332 : c2d Spitzer final data release (DR4) (Evans+, 2003)J/A+A/581/A30 : Herschel maps of {rho} Oph (Rebollido+, 2015)J/A+A/576/A109 : YSOs APEX-CHAMP^+^ high-J CO maps (Yildiz+, 2015)J/ApJS/205/5 : YSO candidates in nearby molecular clouds (Hsieh+, 2013)J/AJ/145/94 : Protostar luminosities from 2 Spitzer surveys (Dunham+, 2013)J/ApJS/201/11 : Mid-IR spectral variability atlas of YSOs (Kospal+, 2012)J/A+A/519/A34 : YSOs in DROXO (Deep rho Oph XMM obs.) (Pillitteri+, 2010)J/AJ/140/1214 : NIR spectroscopic survey of class I YSOs (Connelley+, 2010)J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)J/ApJ/703/1964 : Spectra of three nearby star-forming regions (Furlan+, 2009)J/ApJ/692/973 : Protostars in Perseus, Serpens and Ophiuchus (Enoch+, 2009)J/A+A/498/167 : Embedded sources in L1688 (van Kempen+, 2009)J/ApJ/678/985 : c2d Spitzer survey of interstellar ices. I. (Boogert+, 2008)J/A+A/470/605 : Halpha & [SII] images in HL/XZ Tau region (Movsessian+, 2007)J/A+A/441/181 : Interstellar ^12^C/^13^C ratios (Casassus+, 2005)J/AJ/130/1733 : Optical spectroscopy of {rho} Oph stars (Wilking+, 2005)J/ApJ/566/993 : rho Oph (Lynds 1688) cluster NICMOS imaging (Allen+, 2002)J/A+A/359/113 : X-ray and IR study of Rho Oph dark cloud (Grosso+, 2000)J/ApJ/438/813 : Stellar population in {rho} Oph cloud core (Strom+, 1995)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/813/120https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/813/120http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/813/120https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/813/120https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/813/120http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/813/120GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/813/120/table2 (Summary of observed targets)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/813/120/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/813/120/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/813/120/table2?GETtext/xml+votable180.050000true246.5973333-24.34994440.0055555555555555566/21430 23549 30733 39248 42981 42992 47742https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/813/120?format=asciiInfrareddefaultJ/ApJ/813/120/table2Summary of observed targetsSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLNumber of optical depths measures for this YSOmeta.ref.urlintnullableIDTarget identifiermeta.id;meta.maincharprimarym_ID[ ,NS] Target identifier componentsmeta.code.multipcharf_ID[a] Flag on Target (1)meta.codecharRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainlambda1[2.2/4.8] Lower spectral rangeuminstr.bandwidth;stat.minfloatlambda2[2.3/5] Upper spectral rangeuminstr.bandwidth;stat.maxfloatDateObservation datetime.epoch;obsnullableJ/ApJ/813/120/table4Optical depths and Doppler shifts for CO isotopologue rovibrational lines used in deriving column densitiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDTarget identifiermeta.id;meta.maincharm_ID[NS] Target identifier componentmeta.code.multipcharIsoIsotopologue identifier (12C16O, 12C17O, 12C18O, or 13C16O)meta.id;phys.molcharTransTransitionmeta.id;phys.atmol.transitionchartau[0.02/4.6] Optical depthphys.absorption.opticalDepthfloate_tau[0.001/0.2] The 1{sigma} uncertainty in taustat.errorfloatVLSR[-0.4/10] Local Standard of Rest doppler shift velocitykm/sphys.veloc;pos.lsrfloate_VLSR[0/1] The 1{sigma} uncertainty in VLSRkm/sstat.error;phys.veloc;pos.lsrfloat