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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:0
UID:UW-Physics-Event-2617
DTSTART:20120301T213000Z
DTEND:20120301T230000Z
DTSTAMP:20260420T062447Z
LAST-MODIFIED:20120223T151939Z
LOCATION:4421 Sterling Hall
SUMMARY:Secular Chaos: Formation of Hot Jupiters and the organization 
 of Planetary Systems\, Astronomy Colloquium\, Yoram Lithwick\, Northwe
 stern University
DESCRIPTION:In a planetary system with well-spaced planets\, there is 
 a nonlinear instability that can lead to chaotic behaviour.  One of th
 e planets can gradually become unstable\, in which case its orbit beco
 mes highly eccentric.  This "secular chaos" is known to be responsible
  for the eventual destabilization of Mercury in our own Solar System. 
  Here I focus on systems with multiple giant planets.  I show that aft
 er an extended period of eccentricity diffusion\, the inner planet's p
 ericentre can approach the star to within a few stellar radii. Strong 
 tidal interactions with the star then pull the planet inward\, creatin
 g a hot Jupiter.  In contrast to other proposed channels for the produ
 ction of hot Jupiters\, such a scenario (which I term "secular migrati
 on") explains a range of observations: the pile-up of hot Jupiters at 
 3-day orbital periods\, the fact that hot Jupiters are in general less
  massive than other RV planets\, that they may have misaligned inclina
 tions with respect to stellar spin\, and that they have few easily det
 ectable companions (but may have giant companions in distant orbits). 
  I will also show that if an unstable planet escapes the influence of 
 the other planets\, the remaining planetary system becomes increasingl
 y stable.  This may explain the stable architecture of observed system
 s.
URL:https://www.physics.wisc.edu/events/?id=2617
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