J/ApJ/752/72ivo://CDS.VizieR/J/ApJ/752/72doi:10.26093/cds/vizier.17520072CDSDodson-Robinson S.E.2018-01-02T13:43:14Z2014-03-03T09:24:46ZCDS support team

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

cds-question@unistra.frchemical-abundancesmultiple-starssolar-system-planetsstellar-radiiPrevious studies of the interior structure of transiting exoplanets have shown that the heavy-element content of gas giants increases with host star metallicity. Since metal-poor planets are less dense and have larger radii than metal-rich planets of the same mass, one might expect that metal-poor stars host a higher proportion of gas giants with large radii than metal-rich stars. Here I present evidence for a negative correlation at the 2.3{sigma} level between eclipse depth and stellar metallicity in the Kepler gas giant candidates. Based on Kendall's {tau} statistics, the probability that eclipse depth depends on star metallicity is 0.981. The correlation is consistent with planets orbiting low-metallicity stars being, on average, larger in comparison with their host stars than planets orbiting metal-rich stars. Furthermore, since metal-rich stars have smaller radii than metal-poor stars of the same mass and age, a uniform population of planets should show a rise in median eclipse depth with [M/H]. The fact that I find the opposite trend indicates that substantial changes in the gas giant interior structure must accompany increasing [M/H]. I investigate whether the known scarcity of giant planets orbiting low-mass stars could masquerade as an eclipse depth-metallicity correlation, given the degeneracy between metallicity and temperature for cool stars in the Kepler Input Catalog. While the eclipse depth-metallicity correlation is not yet on firm statistical footing and will require spectroscopic [Fe/H] measurements for validation, it is an intriguing window into how the interior structure of planets and even the planet formation mechanism may be changing with Galactic chemical evolution.2012ApJ...752...72Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/752/72CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toV/133 : Kepler Input Catalog (Kepler Mission Team, 2009)J/A+A/557/A70 : Evolved planet hosts - stellar parameters (Mortier+, 2013)J/A+A/551/A112 : Metallicity-giant planet correlation (Mortier+, 2013)J/ApJ/750/114 : Kepler TTVs. IV. 4 multiple-planet systems (Fabrycky+, 2012)J/ApJ/750/113 : TTVs from Kepler. II. 2 multiplanet systems (Ford+, 2012)J/MNRAS/421/2342 : 4 Kepler systems transit timing obs. (Steffen+, 2012)J/other/Nat/481.475 : RVs of Kepler-34b + Kepler-35b (Welsh+, 2012)J/AJ/143/39 : Analysis of hot Jupiters in Kepler Q2 (Coughlin+, 2012)J/ApJ/738/170 : False positive Kepler planet candidates (Morton+, 2011)J/ApJ/736/19 : Kepler planetary candidates. II. (Borucki+, 2011)J/ApJ/697/544 : Planets orbiting metal-poor dwarfs. II. (Sozzetti+, 2009)J/PASJ/57/109 : Late-G giants abundances (Takeda+, 2005)J/A+A/438/251 : Abundances in stars with giant planets (Beirao+, 2005)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/752/72https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/752/72http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/752/72https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/752/72https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/752/72http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/752/72GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/752/72/table1 (Giant planet candidates used in analysis)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/752/72/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/752/72/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/752/72/table1?GETtext/xml+votable180.050000true289.7397244.647418890.005555555555555556Cone search capability for table J/ApJ/752/72/table2 (Kepler discoveries used for metallicity accuracy analysis)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/752/72/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/752/72/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/752/72/table2?GETtext/xml+votable180.050000true286.8084749.316398890.0055555555555555565/3646 3688 3689 3706 3785 3792 6/14567 14573 14579 14580 14581 14583 14589 14591 14731 14733 14734 14735 14744 14746 14750 14751 14760 14762 14764 14765 14766 14768 14770 14772 14773 14774 14776 14777 14779 14780 14781 14783 14816 14828 14830 14918 14920 14921 14923 14924 14925 14929 14931 14933 14934 14935 14936 14938 14939 14940 14942 14943 14945 14946 14947 14952 14958 14961 14963 14965 14966 14968 14969 14971 14973 14975 15040 15041 15057 15060 15061 15104 15105 15109 15110 15112 15113 15115 15116 15118 15119 15120 15121 15122 15124 15126 15127 15129 15131 15132 15136 15146 15147 15148 15149 15150 15153 15156 15159 15160 15172 15174 15178https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/752/72?format=asciidefaultJ/ApJ/752/72/table1Giant planet candidates used in analysisrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintKOI[5/1587.01] Planet candidate KOI numbermeta.iddoubleKICKIC number of the host starmeta.id;meta.mainintMSimbad column added by the CDSmeta.ref.urlcharRp/R*[0.01/0.3] Planet/star radius ratiophys.size;arith.ratiofloate_Rp/R*[0/0.1]? Rp/R* uncertaintystat.errorfloatnullable[M/H][-1.6/0.6] Host star [M/H]log(Sun)phys.abund.ZfloatKpLink to Kepler planetary candidates data from Cat. J/ApJ/736/19meta.numberintnullableSimbadSimbad column added by the CDSmeta.ref.urlchar_RAPositions from the KIC catalog (Cat. V/133) (right ascension part)degpos.eq.ra;meta.main_DEPositions from the KIC catalog (Cat. V/133) (declination part)degpos.eq.dec;meta.mainJ/ApJ/752/72/table2Kepler discoveries used for metallicity accuracy analysisrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar name (Kepler, KOI, or TrES)meta.idcharKICKIC number (1)meta.id;meta.mainintASimbad column added by the CDSmeta.ref.urlchar[Fe/H][-0.4/0.5] Spectroscopic [Fe/H]log(Sun)phys.abund.Fefloate_[Fe/H][0.02/0.2] [Fe/H] uncertaintylog(Sun)stat.error;phys.abund.FefloatAutAuthor's name of [Fe/H] referencemeta.bib.authorcharBibCodeBibcode of [Fe/H] referencemeta.bib.bibcodecharKpLink to Kepler planetary candidates data from Cat. J/ApJ/736/19meta.numberintnullableSimbadSimbad column added by the CDSmeta.ref.urlchar_RAPositions from the KIC catalog (Cat. V/133) (right ascension part)degpos.eq.ra;meta.main_DEPositions from the KIC catalog (Cat. V/133) (declination part)degpos.eq.dec;meta.main