It has already been shown, using a local model, that accretion discs with cooling times tcool ≤ 3Ω-1 fragment into gravitationally bound objects, while those with cooling times tcool > 3Ω-1 evolve into a quasi-steady state. We present results of three-dimensional simulations that test if the local result still holds globally. We find that the fragmentation boundary is close to that determined using the local model, but that fragmentation may occur for longer cooling times when the disc is more massive or when the mass is distributed in such a way as to make a particular region of the disc more susceptible to the growth of the gravitational instability. These results have significant implications for the formation of gaseous planets in protoplanetary discs and also for the redistribution of angular momentum which could be driven by the presence of relatively massive, bound objects within the disc.
|Title of host publication||Proceedings of the Conference on Towards Other Earths|
|Subtitle of host publication||DARWIN/TPF and the Search for Extrasolar Terrestrial Planets, 22-25 April 2003|
|Editors||M. Fridlund, T. Henning|
|Publisher||ESA PUBLICATIONS DIVISION C/O ESTEC|
|ISBN (Print)||92-9092-849-2, 2003|
|Publication status||Published - 1 Oct 2003|
- Protoplanetary Discs