GIANT PLANETS ORBITING METAL-RICH STARS SHOW SIGNATURES OF PLANET–PLANET INTERACTIONS

By R. Dawson, R. Murray-Clay. 2013

151 citations recorded by the source corpus.

Gas giants orbiting interior to the ice line are thought to have been displaced from their formation locations by processes that remain debated. Here we uncover several new metallicity trends, which together may indicate that two competing mechanisms deliver close-in giant planets: gentle disk migration, operating in environments with a range of metallicities, and violent planet–planet gravitational interactions, primarily triggered in metal-rich systems in which multiple giant planets can form. First, we show with 99.1% confidence that giant planets with semimajor axes between 0.1 and 1 AU orbiting metal-poor stars ([Fe/H] < 0) are confined to lower eccentricities than those orbiting metal-rich stars. Second, we show with 93.3% confidence that eccentric proto-hot Jupiters undergoing tidal circularization primarily orbit metal-rich stars. Finally, we show that only metal-rich stars host a pile-up of hot Jupiters, helping account for the lack of such a pile-up in the overall Kepler sample. Migration caused by stellar perturbers (e.g., stellar Kozai) is unlikely to account for the trends. These trends further motivate follow-up theoretical work addressing which hot Jupiter migration theories can also produce the observed population of eccentric giant planets between 0.1 and 1 AU.

View Paper: https://www.semanticscholar.org/paper/1ddfc043f17915d966a0cb5853adca81f514674e

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1. T. Mazeh
2. Sérgio F. Sousa
3. M. Mayor
4. S. Udry
5. Nuno C. Santos
6. Suzanne Aigrain
7. X. Bonfils
8. A. McQuillan

Citations in the corpus

• STELLAR ROTATION PERIODS OF THE KEPLER OBJECTS OF INTEREST: A DEARTH OF CLOSE-IN PLANETS AROUND FAST ROTATORS (2013, background): “The ending points of the different tracks are determined by the halting mechanism(s) of the planetary migration (Terquem 2003; Dawson & Murray-Clay 2013; Plavchan & Bilinski 2013), and the final stellar rotational period.”
• SWEET-Cat: A catalogue of parameters for Stars With ExoplanETs - I. New atmospheric parameters and masses for 48 stars with planets (2013, background): “…been raised concerning the metallicityorbital period relation (e.g. Queloz et al. 2000; Sozzetti 2004; Santos et al. 2003; Beaugé & Nesvorný 2013; Dawson & Murray-Clay 2013), with hot-jupiters being often pointed out as orbiting particularly metal-rich stars (note however that this tr nd has not…”
• The Occurrence and Architecture of Exoplanetary Systems (2014, background): “Dawson & Murray-Clay (2013) found that giant planets around metal-rich stars have higher eccentricities than similar planets around metal-poor stars.”
• MAKE SUPER-EARTHS, NOT JUPITERS: ACCRETING NEBULAR GAS ONTO SOLID CORES AT 0.1 AU AND BEYOND (2014, background): “The prevalence of super-Earths is consonant with the rarity of Jupiters at these distances (e.g., Jones et al. 2003; Udry et al. 2003; Wright et al. 2012; Fressin et al. 2013; Dawson & Murray-Clay 2013).”
• SOPHIE velocimetry of Kepler transit candidates XVII. The physical properties of giant exoplanets within 400 days of period (2015, unknown): “; Adibekyan et al. 2013; Dawson & Murray-Clay 2013).”
• The GAPS Programme with HARPS-N at TNG - XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets (2017, unknown): “Further support for the HEM is likely provided by the eccentricity-metallicity relation for warm Jupiters, that is Jovian planets with orbital periods 10 P 200 d, first noticed by Dawson & Murray-Clay (2013).”