Collisions of small ice particles under microgravity conditions

Abstract

Planetisimals are thought to be formed from the solid material of a protoplanetary disk by a process of dust aggregation. It is not known how growth proceeds to kilometre sizes, but it has been proposed that water ice beyond the snowline might affect this process. To better understand collisional processes in protoplanetary disks leading to planet formation, the individual low velocity collisions of small ice particles were investigated. The particles were collided under microgravity conditions on a parabolic flight campaign using a purpose-built, cryogenically cooled experimental setup. The setup was capable of colliding pairs of small ice particles (between 4.7 and 10.8 mm in diameter) together at relative collision velocities of between 0.27 and 0.51 m s ^-1 at temperatures between 131 and 160 K. Two types of ice particle were used: ice spheres and irregularly shaped ice fragments. Bouncing was observed in the majority of cases with a few cases of fragmentation. A full range of normalised impact parameters (b/R = 0.0-1.0) was realised with this apparatus. Coefficients of restitution were evenly spread between 0.08 and 0.65 with an average value of 0.36, leading to a minimum of 58% of translational energy being lost in the collision. The range of coefficients of restitution is attributed to the surface roughness of the particles used in the study. Analysis of particle rotation shows that up to 17% of the energy of the particles before the collision was converted into rotational energy. Temperature did not affect the coefficients of restitution over the range studied.

References in corpus (28)

• The effects of snowlines on C/O in planetary atmospheres
• The outcome of protoplanetary dust growth: pebbles, boulders, or planetesimals? II. Introducing the bouncing barrier
• The outcome of protoplanetary dust growth: pebbles, boulders, or planetesimals? I. Mapping the zoo of laboratory collision experiments
• Imaging of the CO Snow Line in a Solar Nebula Analog
• Fluffy dust forms icy planetesimals by static compression
• Water in Star-Forming Regions with the Herschel Space Observatory (WISH): Overview of key program and first results
• Planetesimal formation by sweep-up: How the bouncing barrier can be beneficial to growth
• Free Collisions in a Microgravity Many-Particle Experiment. I. Dust Aggregate Sticking at Low Velocities
• Dust release and tensile strength of the non-volatile layer of cometary nuclei
• Micrometer-sized ice particles for planetary-science experiments - I. Preparation, critical rolling friction force, and specific surface energy
• From dust to planetesimals: an improved model for collisional growth in protoplanetary disks
• High Velocity Dust Collisions: Forming Planetesimals in a Fragmentation Cascade with Final Accretion
• Low-velocity collisions of centimeter-sized dust aggregates
• Water vapor in the protoplanetary disk of DG Tau
• Free Collisions in a Microgravity Many-Particle Experiment III: The Collision Behavior of sub-Millimeter-Sized Dust Aggregates
• Microgravity experiments on the collisional behavior of Saturnian ring particles
• Collisions between equal sized ice grain agglomerates
• The Physics of Protoplanetesimal Dust Agglomerates. Vi. Erosion of Large Aggregates as a Source of Micrometer-Sized Particles
• The effects of disk and dust structure on observed polarimetric images of protoplanetary disks
• Erosion of dust aggregates
• The Physics of Protoplanetesimal Dust Agglomerates. V. Multiple Impacts of Dusty Agglomerates at Velocities Above the Fragmentation Threshold
• Preplanetary scavengers: Growing tall in dust collisions
• The physics of protoplanetesimal dust agglomerates. VII The low-velocity collision behavior of large dust agglomerates
• Impact Angle Influence in High Velocity Dust Collisions during Planetesimal Formation
• Laboratory-based grain-shape models for simulating dust infrared spectra
• Decimetre dust aggregates in protoplanetary discs
• Spatially resolved detection of crystallized water ice in a TTauri object
• A Zero-Gravity Instrument to Study Low Velocity Collisions of Fragile Particles at Low Temperatures

Cited by in corpus (11)

• Contacts of Water Ice in Protoplanetary Disks - Laboratory Experiments
• Grain Growth in the Circumstellar Disks of the Young Stars CY Tau and DoAr 25
• Pebble Accretion and the Diversity of Planetary Systems
• Comet formation in collapsing pebble clouds. What cometary bulk density implies for the cloud mass and dust-to-ice ratio
• Understanding planet formation using microgravity experiments
• Micrometer-Sized Water Ice Particles for Planetary Science Experiments: Influence of Surface Structure on Collisional Properties
• Why are dense planetary rings only found between 8 and 20 AU?
• Thermal Desorption of H2O-Ice: From Nanoscale Films to the Bulk
• Limits on Protoplanet Growth by Accretion of Small Solids
• Collisions of solid ice in planetesimal formation
• Collisions of small ice particles under microgravity conditions (II): Does the chemical composition of the ice change the collisional properties?