Constraining planet structure from stellar chemistry : the cases of CoRoT-7, Kepler-10, and Kepler-93
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Aims. We explore the possibility that the stellar relative abundances of different species can be used to constrain the bulk abundances of known transiting rocky planets. Methods. We use high resolution spectra to derive stellar parameters and chemical abundances for Fe, Si, Mg, O, and C in three stars hosting low mass, rocky planets: CoRoT-7, Kepler-10, and Kepler-93. These planets follow the same line along the mass-radius diagram, pointing toward a similar composition. The derived abundance ratios are compared with the solar values. With a simple stoichiometric model, we estimate the iron mass fraction in each planet, assuming stellar composition. Results. We show that in all cases, the iron mass fraction inferred from the mass-radius relationship seems to be in good agreement with the iron abundance derived from the host star’s photospheric composition. Conclusions. The results suggest that stellar abundances can be used to add constraints on the composition of orbiting rocky planets.
Santos , N C , Adibekyan , V , Mordasini , C , Benz , W , Delgado-Mena , E , Dorn , C , Buchhave , L , Figueira , P , Mortier , A , Pepe , F , Santerne , A , Sousa , S G & Udry , S 2015 , ' Constraining planet structure from stellar chemistry : the cases of CoRoT-7, Kepler-10, and Kepler-93 ' Astronomy & Astrophysics , vol 580 , L13 . DOI: 10.1051/0004-6361/201526850
Astronomy & Astrophysics
© ESO, 2015. Reproduced with permission from Astronomy & Astrophysics, © ESO. This is the final published version of the work, which was originally published at http://dx.doi.org/10.1051/0004-6361/201526850
This work was supported by Fundação para a Ciência e a Tecnologia (FCT) through the research grant UID/FIS/04434/2013. P.F., N.C.S., and S.G.S. also acknowledge support from FCT through Investigador FCT contracts of reference IF/01037/2013, IF/00169/2012, and IF/00028/2014, and POPH/FSE (EC) by FEDER funding through the program “Programa Operacional de Factores de Competitividade − COMPETE”. P.F. acknowledges support from FCT in the form of project reference IF/01037/2013CP1191/CT0001. A.S. is supported by the EU under a Marie Curie Intra-European Fellowship for Career Development with reference FP7-PEOPLE-2013-IEF, number 627202. E.D.M. and V.A. acknowledge the support from FCT in form of the grants SFRH/BPD/76606/2011 and SFRH/BPD/70574/2010. This work results within the collaboration of the COST Action TD 1308. C.M. acknowledges the support from the Swiss National Science Foundation under grant BSSGI0_155816. A.M. received funding from the European Union Seventh Framework Program (FP7/2007-2013) under grant agreement number 313014 (ETAEARTH).
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