J/ApJ/778/132ivo://CDS.VizieR/J/ApJ/778/132doi:10.26093/cds/vizier.17780132CDSTeske J.K.Cunha K.Schuler S.C.Griffith C.A.Smith V.V.2017-12-07T07:27:47Z2015-06-08T10:47:23ZCDS support team

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

cds-question@unistra.frchemical-abundancesline-intensitiesmultiple-starsThe super-Earth exoplanet 55 Cnc e, the smallest member of a five-planet system, has recently been observed to transit its host star. The radius estimates from transit observations, coupled with spectroscopic determinations of mass, provide constraints on its interior composition. The composition of exoplanetary interiors and atmospheres are particularly sensitive to elemental C/O ratio, which to first order can be estimated from the host stars. Results from a recent spectroscopic study analyzing the 6300{AA}[OI] line and two CI lines suggest that 55 Cnc has a carbon-rich composition (C/O=1.12+/-0.09). However, oxygen abundances derived using the 6300{AA}[OI] line are highly sensitive to a Ni I blend, particularly in metal-rich stars such as 55 Cnc ([Fe/H]=0.34+/-0.18). Here, we further investigate 55 Cnc's composition by deriving the carbon and oxygen abundances from these and additional C and O absorption features. We find that the measured C/O ratio depends on the oxygen lines used. The C/O ratio that we derive based on the 6300{AA}[OI] line alone is consistent with the previous value. Yet, our investigation of additional abundance indicators results in a mean C/O ratio of 0.78+/-0.08. The lower C/O ratio of 55 Cnc determined here may place this system at the sensitive boundary between protoplanetary disk compositions giving rise to planets with high (>0.8) versus low (<0.8) C/O ratios. This study illustrates the caution that must applied when determining planet host star C/O ratios, particularly in cool, metal-rich stars.2013ApJ...778..132Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/778/132CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/561/A36 : The LickX Spectra library (Worthey+, 2014)J/ApJ/764/78 : Oxygen abundances in nearby FGK stars (Ramirez+, 2013)J/A+A/547/A91 : Spectroscopic analysis of 348 red giants (Zielinski+, 2012)J/A+A/545/A97 : 0.8-6{mu}m calibrated spectrum of 55 Cnc (Crossfield, 2012)J/A+A/539/A28 : New transit photometry for super-Earth 55Cnc e (Gillon+, 2012)J/ApJ/759/19 : Precise radial velocities of {rho}^1^ Cancri (Endl+, 2012)J/ApJ/757/161 : Spectroscopy of 56 exoplanet host stars (Torres+, 2012)J/A+A/533/A114 : Transit of super-Earth 55 Cnc e (Demory+, 2011)J/A+A/525/A90 : Thick disc vertical properties (Katz+, 2011)J/ApJ/736/87 : Abundances in G-type stars with exoplanets (Kang+, 2011)J/ApJ/736/19 : Kepler planetary candidates. II. (Borucki+, 2011)J/ApJ/735/41 : Carbon and oxygen abundances in FGK stars (Petigura+, 2011)J/ApJ/732/55 : Abundances of stars with planets (Schuler+, 2011)J/ApJ/725/2349 : C/O vs Mg/Si of planetary systems (Delgado Mena+, 2010)J/ApJ/715/1050 : Predicted abundances for extrasolar planets. I. (Bond+, 2010)J/A+A/508/1403 : Oxygen lines in solar granulation. II. (Pereira+, 2009)J/ApJS/168/297 : Stellar parameters of nearby cool stars (Takeda+, 2007)J/A+A/465/271 : Oxygen abundances in nearby stars (Ramirez+, 2007)J/ApJ/646/505 : Catalog of nearby exoplanets (Butler+, 2006)J/ApJ/634/1319 : Synthetic Lick indices (Franchini+ 2005)J/ApJ/626/446 : Effective temperature scale of FGK stars (Ramirez+, 2005)J/ApJ/622/1102 : The planet-metallicity correlation. (Fischer+, 2005)J/A+A/433/185 : Detailed abundance analysis of F and G dwarfs (Bensby+, 2005)J/ApJS/159/141 : Spectroscopic properties of cool stars. I. (Valenti+, 2005)J/PASJ/57/65 : CNO abundances of solar-type stars (Takeda+, 2005)J/A+A/420/183 : Spectroscopy in solar neighborhood (Allende Prieto+ 2004)J/A+A/415/155 : Oxygen abundances in the Galactic disk (Bensby+, 2004)J/A+A/414/351 : ELODIE survey for northern exoplanets III (Naef+, 2004)J/A+A/402/343 : IR OI triplet, [O I] lines in F-K dwarfs/giants (Takeda, 2003)J/A+A/350/955 : Atmospheric param. in metal-poor stars. II (Gratton+, 1999)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/778/132https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/778/132http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/778/132https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/778/132https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/778/132http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/778/132GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/778/132/table1 (*Derived stellar parameters and elemental abundances for 55 Cnc)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/778/132/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/778/132/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/778/132/table1?GETtext/xml+votable180.050000true133.149212228.33081970.0055555555555555566/5009https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/778/132?format=asciiOpticaldefaultJ/ApJ/778/132/table1*Derived stellar parameters and elemental abundances for 55 CncName[55Cnc] Star namemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTeff[5350] Effective temperatureKphys.temperature.effectiveinte_Teff[102] Teff uncertaintyKstat.error;phys.temperature.effectiveintlogg[4.44] Surface gravitylog(cm.s**-2)phys.gravityfloate_logg[0.3] logg uncertaintylog(cm.s**-2)stat.errorfloatVt[1.17] Microturbulent velocity ({xi})km/sphys.velocfloate_Vt[0.14] Vt uncertaintykm/sstat.errorfloat[Fe/H][0.34] Abundance [Fe/H]log(Sun)phys.abund.Fefloate_[Fe/H][0.18] [Fe/H] uncertaintylog(Sun)stat.error;phys.abund.Fefloat[Ni/H][0.43] Abundance [Ni/H]log(Sun)phys.abundfloate_[Ni/H][0.05] [Ni/H] uncertaintylog(Sun)stat.error;phys.abundfloatLink1Display the Equivalent Widths from table2meta.ref.urlcharSimbadSimbad 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.mainJ/ApJ/778/132/table2Lines Measured, Equivalent Widths, and AbundancesExPot[0/9.2] Excitation potentialeVphys.atmol.excitationfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIonIon (C I, O I, Fe I or II, Ni I, or [O I])phys.atmol.ionStagecharlambda[4779/7776] Wavelength in Angstroms0.1nmem.wlfloatlog(gf)[-10.2/0.4] Log of the oscillator strengthphys.atmol.oscStrengthfloatEW0Equivalent width in solar spectrum (m{AA})1e-13mspect.line.eqWidthfloatlogN0[6.1/8.9] Log of solar number abundancephys.abundfloatf_logN0[a] Method used (1)meta.codecharEW55[3.4/104.2] Equivalent width in the 55 Cnc spectrum (m{AA})1e-13mspect.line.eqWidthfloatlogN55[6.5/9.1] Log of 55 Cnc number abundancephys.abundfloatf_logN55[ab] Method used (1)meta.codechar