Oral Presentation

Observational Studies on Formation of Protoplanetary DIsks

Author(s): Yen et al.

Presenter: Hsi-Wei Yen (ESO)

Circumstellar disks around young stellar objects are sites of planet formation, the so-called protoplanetary disks. These disks exhibit Keplerian rotation and typically have radii of a few hundred AU. Understanding the formation mechanism of Keplerian disks is one of the key issues in present astrophysics because it is the starting point to form planetary systems. In this presentation, I will introduce our observational results of Keplerian disks around young protostars and gas kinematics in protostellar sources from 10,000 AU to inner 100 AU scale obtained with single-dish telescopes, SMA, and ALMA. Our results suggest that 100-AU Keplerian disks likely form within the time scale of the Class 0 stage, and the disk growth rate declines in the Class I stage. Furthermore, our recent ALMA observations toward HL Tau show spiral-like structures connecting the central disk, suggesting the dynamics in protostellar sources can be complex in the later evolutionary stage. I will discuss the implication of these results in the context of disk formation and growth.