• DOI:10.1073/pnas.1308261110
• Corpus ID: 30448477

Secular chaos and its application to Mercury, hot Jupiters, and the organization of planetary systems

@article{Lithwick2013SecularCA,
  title={Secular chaos and its application to Mercury, hot Jupiters, and the organization of planetary systems},
  author={Yoram Lithwick and Yanqin Wu},
  journal={Proceedings of the National Academy of Sciences},
  year={2013},
  volume={111},
  pages={12610 - 12615}
}

• Y. Lithwick, Yanqin Wu
• Published 5 November 2013
• Physics, Geology
• Proceedings of the National Academy of Sciences

Significance Planets perturb one another as they orbit their star. These perturbations can build up over a long time, leading to instability and chaos, and, ultimately, to dramatic events such as interplanetary collisions. We focus here on “secular chaos,” which is the chaos that arises in the orbit-averaged equations. We explain how secular chaos works and show that it explains the chaos of Mercury's orbit. We also show that secular chaos could be responsible for the formation of “hot Jupiters,” which are Jupiter-mass planets that orbit very close to their star. Finally, we suggest that secular chaos might be important not only for Mercury and hot Jupiters, but also more generally for organizing a wide variety of extrasolar planetary systems. In the inner solar system, the planets’ orbits evolve chaotically, driven primarily by secular chaos. Mercury has a particularly chaotic orbit and is in danger of being lost within a few billion years. Just as secular chaos is reorganizing the solar system today, so it has likely helped organize it in the past. We suggest that extrasolar planetary systems are also organized to a large extent by secular chaos. A hot Jupiter could be the end state of a secularly chaotic planetary system reminiscent of the solar system. However, in the case of the hot Jupiter, the innermost planet was Jupiter (rather than Mercury) sized, and its chaotic evolution was terminated when it was tidally captured by its star. In this contribution, we review our recent work elucidating the physics of secular chaos and applying it to Mercury and to hot Jupiters. We also present results comparing the inclinations of hot Jupiters thus produced with observations.