What two competing physical processes dominate disk evolution uncertainty?

Answer

Turbulent processes (like Magnetorotational Instability) or disk winds.

A key unresolved theoretical nuance within the standard model concerns the dominant physics driving the evolution of the protoplanetary disk itself, particularly regarding angular momentum transport. Disk evolution profoundly influences the gravitational torques experienced by forming planets, which in turn dictates migration rates. The primary uncertainty lies in whether the necessary transport and viscosity ($\alpha$ parameters) are primarily governed by inherently turbulent processes, such as the Magnetorotational Instability (MRI), or whether they are more strongly influenced by mechanisms involving gas flowing outward, known as disk winds. Settling which of these mechanisms is dominant is crucial because the resulting internal structure and viscosity of the disk directly affect the predictions for how and where planets migrate.

What two competing physical processes dominate disk evolution uncertainty?

Related Questions

What timescale challenge hinders core accretion for forming Jupiter?What subsequent process must the protoplanet model invoke for Hot Jupiters?What velocity limit causes the fragmentation barrier for silicate aggregates?What specific size range creates the effective Radial Drift or "meter-sized barrier"?What initial mass function results from successful streaming instability dominance?Which mechanism attempts to resolve the angular momentum imbalance in the Solar System?What single observation historically limited the scope of early protoplanet theory?How might dominant streaming instability slow terrestrial planet formation timescales?What two competing physical processes dominate disk evolution uncertainty?What non-spherical shape do simulations suggest for planets formed via disk instability?
theorycriticismdisadvantageplanet formationprotoplanet