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SUMMARY:The Dynamics of Planetary Multiplicity - Alexander Mustill (Lund)
DTSTART:20151021T150000Z
DTEND:20151021T160000Z
UID:TALK60721@talks.cam.ac.uk
CONTACT:Dr B.-O. Demory
DESCRIPTION:As the population of known exoplanets grows\, patterns are eme
 rging in the multiplicities of planetary systems. Hot Jupiters\, giant pla
 nets on orbits of a few days\, rarely seem to have close companions\, but 
 often have distant companions (other planets or binary stars beyond 1au). 
 Meanwhile\, Kepler results show that super-Earths and Neptunes within 0.5a
 u are (1) very common (orbiting 50% of stars)\, (2) often in multi-planet 
 systems\, but (3) that there seems to be a separate population of single s
 uper-Earths distinct from the multiple systems.\n\nIn this talk I discuss 
 planetary multiplicities from a dynamical perspective. I first review prop
 osed mechanisms for the migration of Hot Jupiters\, and argue that their l
 ack of close companion planets is consistent with the “dynamical migrati
 on” mechanism of excitation of a high-eccentricity orbit followed by tid
 al circularisation. I then turn my attention to the population of super-Ea
 rths and ask whether the single-planet systems can be the descendants of m
 ultiples as their numbers are culled by dynamical processes (internal inst
 ability\, or scattering or other forcing of undetected planets in the oute
 r system)\, or whether their singledom may date back to the very epoch of 
 planet formation.
LOCATION:Martin Ryle Seminar Room\, Kavli Institute
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