SHAMPOO: A stochastic model for tracking dust particles under the influence of non-local disk processes

Abstract

The abundances of CHNOS are crucial for the composition of planets. At the onset of planet formation, large amounts of these elements are stored in ices on dust grains in planet-forming disks. The evolution of this ice is affected by dynamical transport, collisional processes, and the formation and sublimation of ice. We aim to constrain the disk regions where these processes are fully coupled, and develop a flexible modelling approach that is able to predict the effects of these processes acting simultaneously on the CHNOS budgets of the dust in these regions. We compared timescales associated with these disk processes to constrain the disk regions where this approach is necessary, and developed the SHAMPOO code, which tracks the CHNOS abundances in the ice mantle of a single monomer dust particle, embedded in a larger aggregate and undergoing these processes simultaneously. The adsorption and photodesorption of monomer ices depend on the depth of the monomer in the aggregate. We investigated the effect of fragmentation velocity and aggregate filling factor on the amount of ice on monomers residing at r = 10 AU. The locations where disk processes are fully coupled depend on both grain size and ice species. Monomers embedded in aggregates with fragmentation velocities of 1 m/s are able to undergo adsorption and photodesorption more often compared to a fragmentation velocity of 5 m/s or 10 m/s. Aggregates with a filling factor of $10^{-3}$ are able to accumulate ice 22 times faster on average than aggregates with a filling factor of 1. As different grain sizes are coupled through collisions and the grain ice consists of multiple ice species, it is difficult to isolate the locations where disk processes are fully coupled, necessitating the development of the SHAMPOO code. The processing of ice may not be spatially limited to dust aggregate surfaces for either fragile or porous aggregates.

30 pages, 24 figures, 4 tables, to appear in Astronomy & Astrophysics

References in corpus (18)

• Coagulation, fragmentation and radial motion of solid particles in protoplanetary disks
• Gas- and dust evolution in protoplanetary disks
• Particle Stirring in Turbulent Gas Disks: Including Orbital Oscillations
• Closed-form expressions for particle relative velocities induced by turbulence
• The ancient heritage of water ice in the solar system
• Dust size distributions in coagulation/fragmentation equilibrium: Numerical solutions and analytical fits
• Planet-forming material in a protoplanetary disc: the interplay between chemical evolution and pebble drift
• CO Depletion in Protoplanetary Disks: A Unified Picture Combining Physical Sequestration and Chemical Processing
• Disk evolution, element abundances and cloud properties of young gas giant planets
• Erosion and the limits to planetesimal growth
• Tracing water vapor and ice during dust growth
• Consistent dust and gas models for protoplanetary disks: II. Chemical networks and rates
• Monte Carlo simulation of particle interactions at high dynamic range: Advancing beyond the Googol
• The Physics of Protoplanetesimal Dust Agglomerates II. Low Velocity Collision Properties
• Chemical Feedbacks of Pebble Growth: Impacts on CO depletion and C/O ratios
• Consistent dust and gas models for protoplanetary disks IV. A panchromatic view of protoplanetary disks
• The radial structure of planetary bodies formed by the streaming instability
• Circumplanetary disk ices. I. Ice formation vs. viscous evolution and grain drift