Please use this identifier to cite or link to this item:
http://hdl.handle.net/20.500.12386/30734
Title: | A SUPER-SOLAR METALLICITY FOR STARS WITH HOT ROCKY EXOPLANETS | Authors: | Mulders, Gijs D. Pascucci, Ilaria Apai, Dániel FRASCA, Antonio Molenda-Żakowicz, Joanna |
Issue Date: | 2016 | Journal: | THE ASTRONOMICAL JOURNAL | Number: | 152 | Issue: | 6 | First Page: | 187 | Abstract: | Host star metallicity provides a measure of the conditions in protoplanetary disks at the time of planet formation. Using a sample of over 20,000 Kepler stars with spectroscopic metallicities from the LAMOST survey, we explore how the exoplanet population depends on host star metallicity as a function of orbital period and planet size. We find that exoplanets with orbital periods less than 10 days are preferentially found around metal-rich stars ([Fe/H] ≃ 0.15 ± 0.05 dex). The occurrence rates of these hot exoplanets increases to ∼30% for super-solar metallicity stars from ∼10% for stars with a sub-solar metallicity. Cooler exoplanets, which reside at longer orbital periods and constitute the bulk of the exoplanet population with an occurrence rate of ≳90%, have host star metallicities consistent with solar. At short orbital periods, P\lt 10 days, the difference in host star metallicity is largest for hot rocky planets (\lt 1.7 {R}\oplus ), where the metallicity difference is [Fe/H] ≃ 0.25 ± 0.07 dex. The excess of hot rocky planets around metal-rich stars implies they either share a formation mechanism with hot Jupiters, or trace a planet trap at the protoplanetary disk inner edge, which is metallicity dependent. We do not find statistically significant evidence for a previously identified trend that small planets toward the habitable zone are preferentially found around low-metallicity stars. Refuting or confirming this trend requires a larger sample of spectroscopic metallicities. | URI: | http://hdl.handle.net/20.500.12386/30734 | URL: | https://iopscience.iop.org/article/10.3847/0004-6256/152/6/187 | ISSN: | 0004-6256 | DOI: | 10.3847/0004-6256/152/6/187 | Bibcode ADS: | 2016AJ....152..187M | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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File | Description | Size | Format | |
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Mulders_etal2016.pdf | Mulders et al. 2016, AJ 152, 187 | 2.02 MB | Adobe PDF | View/Open |
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