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Paper: Small Planets Do Not Require a Metal-Rich Environment
Volume: 472, New Quests in Stellar Astrophysics III: A Panchromatic View of Solar-like Stars, With and Without Planets
Page: 91
Authors: Latham, D. W.; Buchhave, L. A.; Kepler Team
Abstract: The abundance of heavy elements in the photospheres of planet-hosting stars similar to the Sun may provide a record of the chemical composition of their initial protoplanetary discs. Several studies have shown that metal-rich stars are much more likely to harbor gas giant planets, thereby supporting the core accretion scenario for giant planet formation. The large sample of transiting planets smaller than Neptune identified by the Kepler mission provides a first opportunity to probe the metallicities of a statistically significant number of stars with small planets. We have derived spectroscopic metallicities for 152 stars hosting 226 planet candidates discovered by Kepler and find that, in contrast to the preference for gas giants to be found around metal-rich stars, the detection of planets smaller than Neptune does not depend as strongly on the metallicity of the host star. Planets smaller than 4 Earth radii are found around host stars with a wide range of metallicities.
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