Speaker: Michael Wilkinson (Department of Mathematics and Statistics, The Open University)

Title: The puzzle of planet formation

Abstract:

I will discuss the difficulties faced by the conventional theory of planet formation, which involves aggregation of microscopic dust particles in a circumstellar disc. These difficulties seem to be becoming more severe as more is discovered about extra-solar planetary systems.
 
I will then describe an alternative hypothesis, termed concurrent collapse, in which planets form by gravitational collapse at the same time as the star about which they orbit. This mechanism avoids theoretical difficulties associated with the conventional model and suggests satisfying explanations for various poorly understood phenomena. It yields new explanations for FU Orionis outbursts seen in young stars, the discovery of exoplanets with eccentric orbits and the existence of small rocky objects such as chondrules in the solar system.
 
The talk reports joint work with Bernhard Mehlig. It is based upon axXiv:0812.2878 and Astrophys. J. Suppl., 176, 484, (2008).

Lunch group: 2