Dust motion and possibility of dust growth in a growing circumstellar disk. Issue 3 (2nd December 2022)

• Record Type: Journal Article
• Authors: Koga, Shunta; Machida, Masahiro N
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 519:Issue 3(2023)
• Page Start: 3595
• Page End: 3610
• Publication Date: 2022-12-02
• Subjects: MHD -- stars: formation -- stars: magnetic field -- dust, extinction -- ISM: jets and outflows; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stac3503
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We calculate the evolution of a star-forming cloud core using a three-dimensional resistive magnetohydrodynamics simulation, treating dust grains as Lagrangian particles, to investigate the dust motion in the early star formation stage. We prepare six different-sized set of dust particles in the range a d = 0.01–$1000\, \mu$ m, where a d is the dust grain size. In a gravitationally collapsing cloud, a circumstellar disk forms around a protostar and drives a protostellar outflow. Almost all the small dust grains ( a d ≲ 10–$100\, \mu$ m) initially distributed in the region θ0 ≲ 45° are ejected from the center by the outflow, where θ0 is the initial zenith angle relative to the rotation axis, whereas only a small number of the large dust grains ($a_{\rm d} \gtrsim 100\, \mu$ m) distributed in the region are ejected. All other grains fall onto either the protostar or disk without being ejected by the outflow. Regardless of the dust grain size, the behavior of the dust motion is divided into two trends after dust particles settle into the circumstellar disk. The dust grains reaching the inner disk region from the upper envelope preferentially fall onto the protostar, while those reaching the outer disk region or disk outer edge from the envelope can survive without an inward radial drift. These surviving grains can induce dust growth. Thus, we expect that the outer disk regions could be a favored place of planet formation.