Formation of Planetesimals by Burgers Vortex

Martin G Abrahamyan

doi:10.11648/j.ijass.20160403.11

Abstract

The effect of a Burgers vortex on formation of planetesimals in a protoplanetary disc in local approach is considered. It is shown that there is not any circular orbit for rigid particles in centrifugal balance; only stable position in Burgers vortex under the influence of centrifugal, Coriolis, pressure gradient and Stokes drag forces is the center of vortex. The two-dimensional anticyclonic Burgers vortex with homogeneously rotating kernel and a converging radial stream of substance can effectively accumulate in its nuclear area the meter-sized rigid particles of total mass ~1028g for characteristic time ~ 106yr.

Highlights

The radial dependence of infra-red, sub mm and cm radiation of protoplanetary disks analyses show that vortices serve as incubators for growth dust particles and formation of planetesimals [1]
The initial stage of growth probably proceeds through the nucleation of sub-micron-sized dust grains from the primordial nebula, which forms the monomers of fractal dust aggregates up to ~ 1mm to ~ 10cm for characteristic time of an order of 103 years
Τs ~ Σ / αΩρ *, (7a) where ρ* is the mass density of a particle, and characteristic time between collisions of rigid particles among themselves is estimated as τcol ~ Dρ* / Σ *Ω, (7b) where D is the diameter of a particle, Σ* is the superficial density of rigid particles in a disk which is more than by two orders less than a disk Σ

Summary

Introduction

The radial dependence of infra-red, sub mm and cm radiation of protoplanetary disks analyses show that vortices serve as incubators for growth dust particles and formation of planetesimals [1]. Long-lived vortical structures in gas disk are a possible way to concentrate the ~10 cm to meter sized particles and to grow up them in planetesimal. In laboratory experiments [14], formation of Burgers vortex which will be considered in the present work is often observed in 2D-turbulent flows. For Keplerian disk, radial momentum equation solution yields to a difference between the speeds of rigid particles and surrounding gas [20]. In the present work the Burgers vortex in a protoplanetary disk and its role in a problem of formation of planetesimals will be considered. We will name this distance “effective radius” of Burgers vortex

The Magnitude of Some Parameters of a Disk

The Burgers Vortex in Local Frame of Reference

The Dynamics of Rigid Particles in Burgers Vortex

Discussion

Conclusion