Dust-Gas Instabilities in Protoplanetary Disks Toward Understanding Planetesimal Formation

How planets form is one of the long-standing questions in astrophysics. In particular, formation scenarios of planetesimals which are kilometer-sized bodies and a precursor of planets are still unclear and under debate although some promising mechanisms have been proposed.

This book highlight disk instabilities that have the potential to explain the origin of planetesimals. Using linear analyses and numerical simulations, it addresses how a disk evolves through the development of instabilities, and also presents a new instability driven by dust coagulation. As a result, the simulation demonstrates a scenario of planetesimal formation: A successive development of multiple instabilities triggers planetesimal formation in resulting dusty rings.

Introduction.- Revision of Macroscopic Equations for Dust Diffusion.- Numerical Simulations of Secular Instabilities.- Coagulation Instability in Protoplanetary Disks.- Summary and Future Prospects.

Ryosuke Tominaga is a Special Postdoctoral Researcher (SPDR fellow) at RIKEN. He received his doctoral degree in Science from Nagoya University in 2021. He was supervised by Prof. Shuichiro Inutsuka, and collaborates with Dr. Sanemichi Z. Takahashi and Dr. Hiroshi Kobayashi. He has been working on dust-gas instabilities in protoplanetary disks to understand how disk substructures form and how planetesimals form from sub-micron dust grains. His research is primarily concerned with numerical simulations and linear analyses.