A Class of Warm Jupiters with Mutually Inclined, Apsidally Misaligned, Close Friends

TL;DR

This paper investigates warm Jupiters with inclined, misaligned orbits, revealing that their observed orbital configurations suggest they are influenced by Kozai-Lidov oscillations caused by outer companions, indicating a non-flat, dynamically active planetary population.

Contribution

It provides observational evidence that warm Jupiters with eccentric companions have mutually inclined orbits oscillating between 35-65 degrees, supporting Kozai-Lidov oscillation models.

Findings

Mutual inclinations oscillate between 35-65 degrees.

Apsidal separations cluster near 90 degrees.

Outer companions' quadrupolar and octupolar potentials influence orbit orientations.

Abstract

The orbits of giant extrasolar planets often have surprisingly small semi-major axes, large eccentricities, or severe misalignments between their normals and their host stars' spin axes. In some formation scenarios invoking Kozai-Lidov oscillations, an external planetary companion drives a planet onto an orbit having these properties. The mutual inclinations for Kozai-Lidov oscillations can be large and have not been confirmed observationally. Here we deduce that observed eccentric warm Jupiters with eccentric giant companions have mutual inclinations that oscillate between 35-65 deg. Our inference is based on the pairs' observed apsidal separations, which cluster near 90 deg. The near-orthogonality of periapse directions is effected by the outer companion's quadrupolar and octupolar potentials. These systems may be undergoing a stalled version of tidal migration that produces warm Jupiters over hot Jupiters, and provide evidence for a population of multi-planet systems that are not flat and have been sculpted by Kozai-Lidov oscillations.