29 Aug 2007 | Anders Johansen, Jeffrey S. Oishi, Mordecai-Mark Mac Low, Hubert Klahr, Thomas Henning & Andrew Youdin
The paper discusses the rapid formation of planetesimals in turbulent circumstellar discs. The authors explore how dust grains collide and grow into larger bodies, a process that is hindered by the radial drift of boulders due to the headwind from slower rotating gas. They propose that gravitational collapse can overcome this barrier, particularly in locally overdense regions of the midplane. The study uses numerical simulations to demonstrate that boulders concentrate in transient high-pressure regions and further enhance their concentration through a streaming instability driven by the relative flow of gas and solids. The simulations show that gravitationally bound clusters form with masses comparable to dwarf planets, offering a possible path to planetesimal formation in accreting circumstellar discs. The authors also highlight the importance of collisional cooling and self-gravity in facilitating gravitational collapse, and discuss the role of magnetorotational turbulence in enhancing the midplane layer's ability to collapse.The paper discusses the rapid formation of planetesimals in turbulent circumstellar discs. The authors explore how dust grains collide and grow into larger bodies, a process that is hindered by the radial drift of boulders due to the headwind from slower rotating gas. They propose that gravitational collapse can overcome this barrier, particularly in locally overdense regions of the midplane. The study uses numerical simulations to demonstrate that boulders concentrate in transient high-pressure regions and further enhance their concentration through a streaming instability driven by the relative flow of gas and solids. The simulations show that gravitationally bound clusters form with masses comparable to dwarf planets, offering a possible path to planetesimal formation in accreting circumstellar discs. The authors also highlight the importance of collisional cooling and self-gravity in facilitating gravitational collapse, and discuss the role of magnetorotational turbulence in enhancing the midplane layer's ability to collapse.