Prompt planetesimal formation beyond the snow line

Journal Article · Thu Sep 01 04:00:00 EDT 2016 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8205/828/1/L2· OSTI ID:22868745

Armitage, Philip J.; Eisner, Josh A. ^[1]

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1. JILA, University of Colorado and NIST, 440 UCB, Boulder, CO 80309-0440 (United States)

We develop a simple model to predict the radial distribution of planetesimal formation. The model is based on the observed growth of dust to millimeter-sized particles, which drift radially, pile-up, and form planetesimals where the stopping time and dust-to-gas ratio intersect the allowed region for streaming instability-induced gravitational collapse. Using an approximate analytic treatment, we first show that drifting particles define a track in metallicity–stopping time space whose only substantial dependence is on the disk’s angular momentum transport efficiency. Prompt planetesimal formation is feasible for high particle accretion rates (relative to the gas, M-dot {sub p}/ M-dot ≳3×10{sup −2} for α=10{sup −2}), which could only be sustained for a limited period of time. If it is possible, it would lead to the deposition of a broad and massive belt of planetesimals with a sharp outer edge. Numerically including turbulent diffusion and vapor condensation processes, we find that a modest enhancement of solids near the snow line occurs for centimeter-sized particles, but that this is largely immaterial for planetesimal formation. We note that radial drift couples planetesimal formation across radii in the disk, and suggest that considerations of planetesimal formation favor a model in which the initial deposition of material for giant planet cores occurs well beyond the snow line.

• OSTI ID: 22868745
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 828; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANGULAR MOMENTUM
APPROXIMATIONS
COSMIC DUST
GRAVITATIONAL COLLAPSE
METALLICITY
MOMENTUM TRANSFER
PLANETS
SOLIDS
SPATIAL DISTRIBUTION
STAR ACCRETION
VAPOR CONDENSATION