J/A+A/632/A32ivo://CDS.VizieR/J/A+A/632/A32doi:10.26093/cds/vizier.36320032CDSMcClure M.K.2020-04-06T14:42:33Z2019-11-25T08:40:44ZCDS support team

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

cds-question@unistra.frvariable-starspre-main-sequence-starsinfrared-astronomyspectroscopyThe carbon content of protoplanetary disks is an important parameter to characterize planets formed at different disk radii. There is some evidence from far-infrared and submillimeter observations that gas in the outer disk is depleted in carbon, with a corresponding enhancement of carbon-rich ices at the disk midplane. Observations of the carbon content inside of the inner sublimation rim could confirm how much cpc on remains locked in kilometer size bodies in the disk. I aim to determine the density, temperature, and carbon abundance inside the disk dust sublimation rim in a set of T Tauri stars with full protoplanetary disks. Using medium-resolution, near-infrared (0.8 to 2.5um) spectra and the new GAIA DR2 distances, I self-consistently determine the stellar, extinction, veiling, and accretion properties of the 26 stars in my sample. From these values, and non-accreting T Tauri spectral templates, I extract the inner disk excess of the target stars from their observed spectra. Then I identify a series of C0 recombination lines in 18 of these disks and use the CHIANTI atomic line database with an optically thin slab model to constrain the average ne, Te, and nC for these lines in the five disks with a complete set of lines. By comparing these values with other slab models of the inner disk using the Cloudy photoionization code, I also constrain nH and the carbon abundance, XC, and hence the amount of carbon 'missing' from the slab. For one disk, DR Tau, I use relative abundances for the accretion stream from the literature to also determine XSi and XN . The inner disks modeled here are extremely dense (nH~10^16^cm^-3^), warm (Te~4500K), and moderately ionized (logXe~3.3). Three of the five modeled disks show robust carbon depletion up to a factor of 42 relative to the solar value. I discuss multiple ways in which the 'missing' carbon could be locked out of the accreting gas. Given the high-density inner disk gas, evidence for radial drift, and lack of obvious gaps in these three systems, their carbon depletion is most consistent with the 'missing' carbon being sequestered in kilometer size bodies. For DR Tau, nitrogen and silicon are also depleted by factors of 45 and 4, respectively, suggesting that the kilometer size bodies into which the grains are locked were formed beyond the N_2_ snowline. I explore briefly what improvements in the models and observations are needed to better address this topic in the future.2019A&A...632A..32Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/632/A32CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/632/A32https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/632/A32http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/632/A32https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/632/A32https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/632/A32http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/632/A32GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/632/A32/list (List of fits spectra)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/632/A32/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/632/A32/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/632/A32/list?GETtext/xml+votable180.050000true64.815958329.10747220.0055555555555555565/292 6/368 1031 1039 1050-1052 1054 1063 1073 1075 1082-1083 1114 1124 1156 1159 23518 23543 23549 24201 24205 24300 33123https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/632/A32?format=asciiInfrareddefaultJ/A+A/632/A32/table1*Targets and derived stellar parametersSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarCentral star namemeta.id;meta.maincharObs.dateDate of observationtime.epochnullableSpTypeMK stellar spectral typesrc.spTypecharTeffEffective stellar temperatureKphys.temperature.effectiveintAVExtinction along the line of sightmagphys.absorptionfloate_AVrms uncertainty on AVmagstat.errorfloatDistDistance to the star (1)pcpos.distance;pos.heliocentricfloatE_Dist? Error on AV (upper value)pcstat.error;stat.maxfloatnullablee_Dist? Error on AV (lower value)pcstat.errorfloatnullableL*Stellar luminositysolLumphys.luminosityfloatLBrg? Luminosity in the H0 Br{gamma} linesolLumphys.luminosity;em.gammadoublenullableLacc? Accretion luminosity derived from Br{gamma}solLumphys.luminositydoublenullablefsh? Filling factor of the accretion shock on the central starstat.fit.paramdoublenullableR*Stellar radiussolRadphys.size.radiusfloatM*Stellar mass (2)solMassphys.massfloatAgeStellar age from the same tracksMyrtime.agefloatdM/dt? Mass accretion rate derived from Br{gamma} (3)solMass/yrarith.rate;phys.massdoublenullable<rJ>Mean J-band veilingphys.absorptionfloatspShow the spectrummeta.ref.urlcharFileNameName of the fits file with spectrummeta.id;meta.fitscharJ/A+A/632/A32/table2*Integrated fluxes for major line complexes of C^0^ and H^0^ Br{gamma} observed in this samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintStarStar namemeta.id;meta.maincharF0.908umIntegrated flux for line at 0.908um (1)mW.m**-2phot.flux.density;em.IRdoubleS/N0.908umS/N for line at 0.908umstat.snrcharF0.94umIntegrated flux for line at 0.94um (1)mW.m**-2phot.flux.density;em.IRdoubleS/N0.94umS/N for line at 0.94umstat.snrcharF1.069umIntegrated flux for line at 1.069um (1)mW.m**-2phot.flux.density;em.IRdoubleS/N1.069umS/N for line at 1.069umstat.snrcharF1.176umIntegrated flux for line at 1.176um (1)mW.m**-2phot.flux.density;em.IRdoubleS/N1.176umS/N for line at 1.176umstat.snrcharF1.45um? Integrated flux for line at 1.45um (1)mW.m**-2phot.flux.density;em.IRdoublenullableS/N1.45umS/N for line at 1.45umstat.snrcharF2.166um? Integrated flux for line at 2.166um (1)mW.m**-2phot.flux.density;em.IRdoublenullableS/N2.166um? S/N for line at 2.166umstat.snrfloatnullableNotesNotesmeta.notecharJ/A+A/632/A32/listList of fits spectraNxNumber of pixels along X-axismeta.numberintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainStarStar namemeta.id;meta.maincharsizeSize of FITS fileKibytephys.size;meta.fitsintspShow the spectrummeta.ref.urlcharFileNameName of FITS file, in subdirectory spmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitscharSimbadSimbad column added by the CDSmeta.ref.urlchar