• Publications
  • Influence
Dynamics and Origin of the 2:1 Orbital Resonances of the GJ 876 Planets
The discovery by Marcy and coworkers of two planets in 2 : 1 orbital resonance about the star GJ 876 has been supplemented by a dynamical fit to the data by Laughlin & Chambers, which places theExpand
The tides of Io
Abstract The Galilean satellites Io, Europa, and Ganymede interact through several stable orbital resonances where λ 1 − 2λ 2 + ω 1 = 0, λ 1 − 2λ 2 + ω 2 = 180°, λ 2 − 2λ 3 + ω 2 = 0 and λ1 − 3λ2 +Expand
Large Longitude Libration of Mercury Reveals a Molten Core
Observations of radar speckle patterns tied to the rotation of Mercury establish that the planet occupies a Cassini state with obliquity of 2.11 ± 0.1 arc minutes, and indicate that the mantle of Mercury is decoupled from a core that is at least partially molten. Expand
Melting of Io by Tidal Dissipation
The dissipation of tidal energy in Jupiter's satellite Io is likely to have melted a major fraction of the mass. Consequences of a largely molten interior may be evident in pictures of Io's surfaceExpand
Contribution of tidal dissipation to lunar thermal history.
Abstract The possible contributions of tidal heating to lunar thermal history are investigated. Analytic determinations of tidal dissipation in a homogeneous, incompressible Moon and in a two-layerExpand
The chaotic rotation of Hyperion
Abstract A plot of spin rate versus orientation when Hyperion is at the pericenter of its orbit (surface of section) reveals a large chaotic zone surrounding the synchronous spin-orbit state ofExpand
Recent discoveries of several transiting planets with clearly non-zero eccentricities and some large obliquities started changing the simple picture of close-in planets having circular andExpand
Gravity Field and Internal Structure of Mercury from MESSENGER
The results point to an interior structure that differs from those of the other terrestrial planets: the density of the planet's solid outer shell suggests the existence of a deep reservoir of high-density material, possibly an Fe-S layer. Expand
The curious case of Mercury's internal structure
United States. National Aeronautics and Space Administration (NASA MESSENGER Participating Scientist grant NNX07AR77G)