[Baps] Talk by Doug Lin, Monday April 11, 12:30 pm, CfA

[Sarah T. Stewart-Mukhopadhyay]

DATE: MONDAY, APR 11
TIME: 12:30 pm
ROOM: Pratt Conference Room, Harvard-Smithsonian Center for Astrophysics, 60
Garden St. 
SPEAKER: Dr. Douglas Lin (Lick Observatory)

"A Transition from Chaos to Order during the Emergence of Terrestrial
Planets in the Solar System"

Abstract

The conventional sequential accretion scenario for the planet formation is
based on the assumption that the solid cores form through cohesive
collisions prior to any potential gas accretion. The prerequisite of
planetesimals' orbit crossing is in contrast with the present-day low
eccentricity of the terrestrial planets. The late giant impact scenario for
the origin of the Moon is also in conflict with the nearly circular orbit of
the Earth.  A potential resolution for these paradoxes is suggested.  During
the depletion of the primordial solar nebula, Jupiter's secular resonance
sweeps through the inner solar system. The eccentricity of the planetesimals
is regulated by the excitation due to the passage of the sweeping secular
resonance and damping due to their tidal interaction with the residual disk
gas. Under the combined influence of these two effects, the collision
frequency and growth rate of the planetesimals are enhanced.  They also
become detached from the resonance and attain low-eccentricity orbits when
their mass becomes comparable to that of the Earth.  With this scenario, we
discuss its implications on the clearing efficiency of the asteroid belt,
the delivery of water to the Earth, and the time scales for the final
assemblage of the terrestrial planets.


Map and directions: 
http://cfa-www.harvard.edu/mapsdir.html