Stability of Multiple Planetary Systems

TYPEAstrophysics Seminar
Speaker:Alice Quillen
Affiliation:Rochester University
Organizer:Hagai Perets
Time:15:30 - 16:30
Location:Lidow 605
Abstract:Multiple planet and satellite systems are affected by three-body and
secular resonances affecting short timescale behavior and long
timescale stability. I will discuss theoretical scenarios that
account for stability timescales measured numerically for closely
spaced planetary systems, such as closely spaced Kepler multiple
planet systems and the Uranian satellite system. Three-body
resonances, constructed of two non-resonant zero-th order two-body
terms are sufficiently dense to account for wander in semi-major axis
seen in numerical integrations of some closely spaced systems and they
are likely the cause of instability of these systems. A resonance
overlap criterion is derived with three-body resonances overlapping
when interplanetary separation is less than an order unity factor
times the planet mass to the one quarter power. This represents a
first attempt to account for numerically measured stability times in
closely spaced multiple planet systems. When systems are in low
order two-body resonances, stability timescales can be either reduced
or increased. I will also discuss the capture and stability of
systems in resonant chains, where each consecutive pair of bodies is
in or near a low order two-body resonance, such as inferred in the
HR8799 and KOI 730 planetary systems.