Planet Formation in Radiatively Inefficient Protoplanetary Discs.
Abstract
I examine the effects on planetary system formation of radiatively
inefficient disc models where positive corotation torques may counter
the rapid inward migration of low-mass planets driven by Lindblad
torques. I use N-body simulations coupled with algorithms to model
the evolution of the gas disc, type I migration, gap formation and type
II migration, planetary atmospheres that enhance the probability of
planetesimal accretion by protoplanets, gas accretion on to forming
planetary cores and gas disc dispersal.
The inclusion of entropy and vorticity related corotation torques can
lead to a net positive torque thus giving rise to outward migration of
planets. This can allow larger planets to survive for a longer period of
time, allowing some planets to accrete enough gas within the lifetime
of the disc to undergo runaway gas accretion thus forming gas giant
planets.
I review the current status of extrasolar planet observations and the
methods with which these observations are made, and provide a contextual
review of the theory of planet formation.
Using these models, I have successfully formed a number of gas giant
planets with semi-major axes ranging from 0.1 AU up to 75 AU and
masses from 100 Earth masses through to 700 Earth masses, as well
as a large number of terrestrial sized planets. In later simulations, a
large number of super-Earth, Neptune-mass and gas planets that are
too small to be considered giants were formed also.
Authors
Hellary, PhilCollections
- Theses [3709]