Resonant repulsion of kepler planet pairs

Yoram Lithwick*, Yanqin Wu

*Corresponding author for this work

Research output: Contribution to journalArticle

112 Scopus citations

Abstract

Planetary systems discovered by the Kepler space telescope exhibit an intriguing feature. While the period ratios of adjacent low-mass planets appear largely random, there is a significant excess of pairs that lie just wide of resonances and a deficit on the near side. We demonstrate that this feature naturally arises when two near-resonant planets interact in the presence of weak dissipation that damps eccentricities. The two planets repel each other as orbital energy is lost to heat. This moves near-resonant pairs just beyond resonance, by a distance that reflects the integrated dissipation they experienced over their lifetimes. We find that the observed distances may be explained by tides if tidal dissipation is unexpectedly efficient (tidal quality factor ∼10). Once the effect of resonant repulsion is accounted for, the initial orbits of these low-mass planets show little preference for resonances. This could constrain their origin.

Original languageEnglish (US)
Article numberL11
JournalAstrophysical Journal Letters
Volume756
Issue number1
DOIs
StatePublished - Aug 24 2012

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Keywords

  • planets and satellites: dynamical evolution and stability

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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