English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Incremental particle growth in turbulent protoplanetary nebulae is limited bya combination of barriers that can slow or stall growth. Moreover, particlesthat grow massive enough to decouple from the gas are subject to inward radialdrift which could lead to the depletion of most disk solids beforeplanetesimals can form. Compact particle growth is probably not realistic.Rather, it is more likely that grains grow as fractal aggregates which mayovercome this so-called radial drift barrier because they remain more coupledto the gas than compact particles of equal mass. We model fractal aggregategrowth and compaction in a viscously evolving solar-like nebula for a range ofturbulent intensities $\alpha_{\rm{t}} = 10^{-5}-10^{-2}$. We do find thatradial drift is less influential for porous aggregates over much of theirgrowth phase; however, outside the water snowline fractal aggregates can growto much larger masses with larger Stokes numbers more quickly than compactparticles, leading to rapid inward radial drift. As a result, disk solidsoutside the snowline out to $\sim 10-20$ AU are depleted earlier than incompact growth models, but outside $\sim 20$ AU material is retained muchlonger because aggregate Stokes numbers there remain lower initially.Nevertheless, we conclude even fractal models will lose most disk solidswithout the intervention of some leap-frog planetesimal forming mechanism suchas the Streaming Instability (SI), though conditions for the SI are generallynever satisfied, except for a brief period %for a brief stage around $\sim 0.2$Myr at the snowline for $\alpha_{\rm{t}}=10^{-5}$.

Global Modeling of Nebulae With Particle Growth, Drift, and Evaporation Fronts. II. The Influence of Porosity on Solids Evolution