Sergei Nayakshin - September 30, 2016

Formation of brown dwarfs, planets and planetary debris: theories versus observations

Kuiper (1951) suggested that all planets start forming by gravitational instability of
a massive protoplanetary disc. His ideas however could not be made self-consistent
without planet migration which was not known at the time. Tidal Downsizing hypothesis
is the modern version of this scenario in which migration of planets plays a key role.
Detailed simulations of self-gravitating discs, gas fragments, dust grain dynamics,
and planet evolutionary calculations are summarised and used to build a predictive
planet formation model and population synthesis. A new interpretation of exoplanetary
and debris disc data, the Solar System's origins, and the links between planets and
brown dwarfs is offered. This interpretation is contrasted with the current
observations and the predictions of the Core Accretion theory. Observations that can
distinguish the two scenarios are pointed out.