Johnson, John Asher and Aller, Kimberly M. and Howard, Andrew W. and Crepp, Justin R. (2010) Giant Planet Occurrence in the Stellar Mass-Metallicity Plane. Publications of the Astronomical Society of the Pacific, 122 (894). pp. 905-915. ISSN 0004-6280 http://resolver.caltech.edu/CaltechAUTHORS:20100825-084335137
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Correlations between stellar properties and the occurrence rate of exoplanets can be used to inform the target selection of future planet-search efforts and provide valuable clues about the planet-formation process. We analyze a sample of 1266 stars drawn from the California Planet Survey targets to determine the empirical functional form describing the likelihood of a star harboring a giant planet as a function of its mass and metallicity. Our stellar sample ranges from M dwarfs with masses as low as 0.2 M_⊙ to intermediate-mass subgiants with masses as high as 1.9 M_⊙. In agreement with previous studies, our sample exhibits a planet-metallicity correlation at all stellar masses; the fraction of stars that harbor giant planets scales as f ∝ 10^(1.2[Fe/H]). We can rule out a flat metallicity relationship among our evolved stars (at 98% confidence), which argues that the high metallicities of stars with planets is not likely due to convective envelope “pollution.” Our data also rule out a constant planet occurrence rate for [Fe/H] < 0, indicating that giant planets continue to become rarer at sub-Solar metallicities. We also find that planet occurrence increases with stellar mass (f ∝ M_*), characterized by a rise from 3% around M dwarfs (0.5 M_⊙) to 14% around A stars (2 M_⊙), at Solar metallicity. We argue that the correlation between stellar properties and giant planet occurrence is strong supporting evidence of the core-accretion model of planet formation.
|Additional Information:||© 2010 The Astronomical Society of the Pacific. Received 2010 April 15; accepted 2010 June 11; published 2010 July 22. We gratefully acknowledge Debra Fischer, Geoff Marcy, and Brendan Bowler for their helpful suggestions, edits, and comments. We thank Michael Fitzgerald, Jon Swift, Michael Cushing, Jason Wright, and Brendan Bowler for their illuminating discussions about Bayesian inference and other statistical methods. Thanks to Scott Kenyon, Sally Dodson-Robinson, and Christoph Mordasini for their comments on earlier drafts of this article, and we acknowledge the careful edits and thoughtful suggestions of the anonymous referee. J. A. J. acknowledges the NSF Astronomy and Astrophysics Postdoctoral Fellow with support from NSF grant AST-0702821 for supporting the research leading up to this work. K. M. A.’s research was supported by the University of Hawaii Institute for Astronomy Research Experiences for Undergraduates (REU) Program, which is funded by the National Science Foundation through grant AST-0757887. A.W.H. gratefully acknowledges support from a Townes Postdoctoral Fellowship at the University of California, Berkeley Space Sciences Laboratory. This publication makes use of the SIMBAD database operated at CDS, Strasbourg, France; NASA’s Astrophysics Data System Bibliographic Services; and the Exoplanet Data Explorer at http:// exoplanets.org/.|
|Official Citation:||Giant Planet Occurrence in the Stellar Mass-Metallicity Plane John Asher Johnson, Kimberly M. Aller, Andrew W. Howard, and Justin R. Crepp Publications of the Astronomical Society of the Pacific 2010 122:894, 905-915|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||08 Sep 2010 17:32|
|Last Modified:||26 Dec 2012 12:21|
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