Supervisor : Dr Sergei Nayakshin (sn85@astro.le.ac.uk)

Details of Project

Massive gas discs take a leading role in formation and evolution of most astronomical objects, from planets and stars to super-massive black holes (SMBH) and galaxies hosting them. We currently understand that when these discs are able to cool rapidly,they form spiral arms due to the disc self-gravitational instability. The non-linear evolution is not clear at all, however.

A gas/dust disc of 0.4 Solar masses orbiting a 0.6 Solar masses star fragments into gas clumps. The gas clumps do not stay where they formed, interacting and usually migrating closer to the star. Most are then disrupted by the star, contributing to the star's growth and leaving terrestrial-like planets behind. <br />

Our group is internationally well known for our work on formation of stars in the disc in the centre of our Galaxy (Nayakshin et al 2007, Monthly Notices of the Royal Astronomical Society, Volume 379, Issue 1, pp. 21-33) and the new planet formation model (Nayakshin 2010, Monthly Notices of the Royal Astronomical Society: Letters, Volume 408, Issue 1, pp. L36-L40).  Our simulations show (cf. the Figure) that the spiral arms break into numerous massive gas clumps, progenitors of planets, stars or star clusters. However, we find that these clumps may migrate rapidly closer to the central object, leading to radically different results from what has been previously expected. This effects is of primary importance for planet formation and SMBH/galaxy evolution, and there is a whole range of exciting projects in these areas.

The PhD student is expected to have a suitably strong background in theoretical physics/astrophysics and capable or willing to learn to run large scale numerical simulations. We prefer an academically oriented applicant capable of continuing the career in theoretical astrophysics after the PhD.

Background Reading

A Numerical Simulation of a "Super-Earth" Core Delivery from ~ 100 AU to ~ 8 AU