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SUMMARY:Resonances as a record of planetary migration - Cuk\, M (Harvard)
DTSTART:20091111T151000Z
DTEND:20091111T153000Z
UID:TALK21417@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:While hundreds of extrasolar planetary systems have been disco
 vered\, only a small fraction of them contain more than one known planet. 
 An even smaller fraction of known multi-planet systems are relatively comp
 act\, containing giant planet pairs with period ratios below three or four
  (Saturn-to-Jupiter period ratio is about 2.5). Most multi-planet systems 
 contain planet pairs on eccentric orbits\, with orbital periods varying by
  orders of magnitude. This is almost certainly a consequence of planet-pla
 net scattering\, which would have erased much of information about the pri
 or dynamical evolution of the system. \n\nCurrent theory of planet formati
 on suggests that there are generally two epochs of giant planet migration:
  one caused by interactions with the gas disk within the first few Myr of 
 the system's history\, and a later one (possibly lasting for tens to hundr
 eds of Myr)\, driven by gravitational interaction between the planets and 
 solid planetesimals. Planets with smaller masses are expected to be affect
 ed more by interactions with planetesimals\, due to the limited amount of 
 mass available as solids (cf. Raymond and Armitage 2009). \n\nWe note that
  very massive known compact exoplanet pairs tend to occupy resonances more
  often than those with masses similar to Jupiter and Saturn. Using numeric
 al simulations\, we show that the non-resonant compact pairs can be plausi
 bly derived from an initial resonant or near-resonant configuration\, much
  like the Nice model (Tsiganis et al. 2005) proposes for our solar system.
  We conclude that the gas-driven migration might be often ending with many
  of the planets in resonances\, despite the effects of turbulence (Adams e
 t al. 2008). It is possible that after the gas has dissipated\, the scatte
 ring of sizable solid protoplanets enables resonance-breaking in less mass
 ive systems but not in more massive ones. We propose observational tests o
 f these hypotheses.
LOCATION:Satellite
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