Matthew J. Holman

Long-term stability of horseshoe orbits

Unlike Trojans, horseshoe coorbitals are not generally considered to be long-term stable (Dermott & Murray 1981a; Murray & Dermott 1999). As the lifetime of Earth’s and Venus’s horseshoe coorbitals is expected to be about a Gyr, we investigated the possible contribution of late-escaping inner planet coorbitals to the lunar Late Heavy Bombardment. Contrary to analytical estimates, we do not find many horseshoe objects escaping after the first 100 Myr. In order to understand this behaviour, we ran a second set of simulations featuring idealized planets on circular orbits with a range of masses. We find that horseshoe coorbitals are generally long lived (and potentially stable) for systems with primary-to-secondary mass ratios larger than about 1200. This is consistent with the results of Laughlin & Chambers (2002) for equal-mass pairs of coorbital planets and the instability of Jupiter’s horseshoe companions (Stacey & Connors 2008). Horseshoe orbits at smaller mass ratios are unstable because they must approach within 5 Hill radii of the secondary. In contrast, tadpole orbits are more robust and can remain stable even when approaching within 4 Hill radii of the secondary.

Characterization of the K2-19 Multiple-Transiting Planetary System via High-Dispersion Spectroscopy, AO Imaging, and Transit Timing Variations

K2-19 (EPIC201505350) is an interesting planetary system in which two transiting planets with radii ~ 7

Dynamical Chaos in the Wisdom-Holman Integrator: Origins and Solutions

R_{Earth}

The Pan-STARRS Synthetic Solar System Model and its Applications

(inner planet b) and ~ 4

The Transit Light Curve (TLC) Project

R_{Earth}

High-Precision Imaging Photometers for the Transient Exoplanet Survey Satellite

(outer planet c) have orbits that are nearly in a 3:2 mean-motion resonance. Here, we present results of ground-based follow-up observations for the K2-19 planetary system. We have performed high-dispersion spectroscopy and high-contrast adaptive-optics imaging of the host star with the HDS and HiCIAO on the Subaru 8.2m telescope. We find that the host star is relatively old (>8 Gyr) late G-type star (

Sub-Kilometer Asteroid Diameter Survey (SKADS) V1.0

T_{eff}

The Luminosity Function of the Trans-Neptunian Region

~ 5350 K,

The Apparently Decaying Orbit of WASP-12b

M_s

THE TRANSIT LIGHT CURVE PROJECT. XIV. CONFIRMATION OF ANOMALOUS RADII FOR THE EXOPLANETS TRES-4b, HAT-P-3b, AND WASP-12b

~ 0.9