Planetesimal formation in turbulent protoplanetary disks

Min-Kai Lin^1*, Kan Chen^1,2, Yen-Chien Chang³, Yueh-Ning Lee⁴

¹ASIAA, Academia Sinica, Taipei, Taiwan
²Institute of Astronomy, University of Cambridge, Cambridge, UK
³Department of Mathematics, Fu-Jen Catholic University, New Taipei City, Taiwan
⁴Department of Earth Sciences, National Taiwan Normal University, Taipei, Taiwan

* Presenter:Min-Kai Lin, email:mklin@asiaa.sinica.edu.tw

The growth of small dust grains into planetesimals --- the building block of planets --- is a key stage in modern planet formation theory. However, this process is plagued by a number of obstacles, including turbulence. Several mechanisms have been identified that can lead to turbulence in protoplanetary disks, which can hinder the collapse of dust grains into planetesimals. Although it is now possible to directly simulate dust interacting with a turbulent disk, analytical models are nevertheless desirable to explore parameter space more fully, as well as obtaining physical insight. We present the linear theory of dusty, turbulent gas with focus on how turbulence affects the `streaming instability' in dusty gas, which is thought to trigger planetesimal formation. We find that the streaming instability is sensitive to turbulence, and is easily quenched in typical disk models, especially for small particles. Thus, planetesimal formation can only proceed in sufficiently laminar regions of protoplanetary disks. We will also present the first analysis of the streaming instability in stratified disks.

Keywords: planet formation, dust dynamics, protoplanetary disks, fluid dynamics