Oral Presentation

A New Mechanism for the Ring and Spiral Formation in Protoplanetary Disks and Implications for Observations

Author(s): Hui Li (LANL)

Presenter: Hui Li (Los Alamos National Laboratory)

We find that protoplanetary disks may spontaneously generate multiple,
concentric gas rings without an embedded planet through an eccentric cooling instability. Using
both linear theory and non-linear hydrodynamics simulations, we show that a variety of
background states may trap a slowly precessing, one-armed spiral mode that becomes unstable
when a gravitationally-stable disk rapidly cools. We verify the instability evolution and ring
formation mechanism from first principles with our linear theory, which shows remarkable
agreement with the simulation results. Dust trapped in these rings may produce observable
features consistent with observed disks. Additionally, direct detection of the eccentric gas
motions may be possible when the instability saturates, and any residual eccentricity left over
in the rings at later times may also provide direct observational evidence of this mechanism.