DUST CONCENTRATION AT THE BOUNDARY BETWEEN STEADY SUPER/SUB-KEPLERIAN FLOW CREATED BY INHOMOGENEOUS GROWTH OF MAGNETO-ROTATIONAL INSTABILITY

Journal Article · Mon May 10 04:00:00 EDT 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/714/2/1155· OSTI ID:21448849

Kato, M T; Ida, S ^[1]; Fujimoto, M ^[2]

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1. Department of Earth and Planetary Science, Tokyo Institute of Technology, Ookayama 2-1-12-I2-10, Meguro-ku, Tokyo (Japan)
2. Institute of Space and Astronomical Science, Japan Aerospace Exploration Agency, Yoshinodai 3-1-1, Sagamihara, Kanagawa (Japan)

How planetesimals are created from tiny dust particles in a proto-planetary disk before the dust particles spiral to the central star is one of the most challenging problems in the theory of planetary system formation. In our previous paper, we have shown that a steady angular velocity profile that consists of both super- and sub-Keplerian regions is created in the disk through non-uniform excitation of magneto-rotational instability (MRI). Such non-uniform MRI excitation is reasonably expected in a part of disks with relatively low ionization degree. In this paper, we show through three-dimensional resistive MHD simulations with test particles that this radial structure of the angular velocity indeed leads to the prevention of spiral-in of dust particles and furthermore to their accumulation at the boundary of super-Keplerian and sub-Keplerian regions. Treating dust particles as test particles, their motions under the influence of the non-uniform MRI through gas drag are simulated. In the most favorable cases (meter-size dust particles in the disk region with a relatively large fraction of MRI-stable region), we found that the dust concentration is peaked around the super/sub-Keplerian flow boundary and the peak dust density is 10,000 times as high as the initial value. The peak density is high enough for the subsequent gravitational instability to set in, suggesting a possible route to planetesimal formation via non-uniformly excited MRI in weakly ionized regions of a disk.

• OSTI ID: 21448849
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 714; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANGULAR VELOCITY
DUSTS
FLUID MECHANICS
GRAVITATIONAL INSTABILITY
HYDRODYNAMICS
INSTABILITY
IONIZATION
MAGNETOHYDRODYNAMICS
MECHANICS
PLANETS
PLASMA INSTABILITY
PROTOPLANETS
SATELLITES
SIMULATION
STARS
VELOCITY