Title: Accretion bursts and prospects for planetesimal formation in protoplanetary disks around young stars
Speaker: Indrani Das (ASIAA)
Date: November 22 at 14:30
Location: R521, General Building II
Abstract:
We investigate the occurrence of episodic accretion bursts, dust accumulation, and the prospects for planetesimal formation in a gravitationally unstable (GI) magnetized protoplanetary disk with triggered magnetorotational instability (MRI), in low and intermediate mass stars. We use numerical magnetohydrodynamics simulations in the thin-disk limit to model the formation and long-term evolution of a gravitationally unstable magnetized protoplanetary disk, including dust dynamics and growth. Dust rings that are susceptible to streaming instability (SI) form within the inner disk region owing to the radially varying strength of GI. Gradual warming of the dust rings, thanks to high opacity, increases the gas temperature above a threshold for the MRI to develop via thermal ionization of alkaline metals. The characteristics of ensuing bursts are analyzed and compared to their cousins in low-mass stars. Additionally, we analyze the effects of dust sublimation within these dusty rings forming near the central protostar. Our work shows that GI-induced dusty rings within the inner disk around young protostars, while initially susceptible to streaming instability, tend to shrink or be destroyed over time due to periodic accretion bursts. Our results also suggest whether a disk around young low-mass and intermediate mass stars may provide environments conducive to planetesimal formation via SI.
