The origin of retrograde hot Jupiters

Smadar Naoz, Will M. Farr, Yoram Lithwick, Frederic A. Rasio, Jean Teyssandier

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Many hot Jupiters are observed to be misaligned with respect to the rotation axis of the star (as measured through the Rossiter-McLaughlin effect) and some (about 25%) even appear to be in retrograde orbits. We show that the presence of an additional, moderately inclined and eccentric massive planet in the system can naturally explain close, inclined, eccentric, and even retrograde orbits. We have derived a complete and accurate treatment of the secular dynamics including both the key octupole-order effects and tidal friction. The flow of angular momentum from the inner orbit to the orbit of the perturber can lead to both high eccentricities and inclinations, and even flip the inner orbit. In our treatment the component of the inner orbit's angular momentum perpendicular to the stellar equatorial plane can change sign; a brief excursion to very high eccentricity during the chaotic evolution of the inner orbit can then lead to rapid tidal capture, forming a retrograde hot Jupiter. Previous treatments of the secular dynamics focusing on stellar-mass perturbers would not allow for such an outcome, since in that limit the component of the inner orbit's angular momentum perpendicular to the stellar equatorial plane is strictly conserved. Thus, the inclination of the planet's orbit could not change from prograde to retrograde.

Original languageEnglish (US)
Title of host publicationThe Astrophysics of Planetary Systems
Subtitle of host publicationFormation, Structure, and Dynamical Evolution
EditorsAlessandro Sozzetti, Mario Lattanzi, Alan Boss
Number of pages4
StatePublished - Oct 2010

Publication series

NameProceedings of the International Astronomical Union
ISSN (Print)1743-9213
ISSN (Electronic)1743-9221


  • Planetary systems: formation
  • Planets and satellites: formation

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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