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/

Zendy Open

Presents the pdf analysis as premium feature

PDF Analysis

Insights

Presents the summarisation as premium feature

Summarisation

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

The bouncing barrier, a parameter combination at which dust particles in theprotoplanetary disk always rebound in mutual collisions, is one of the crucialsteps of planet formation. In the past years, several experiments have beenperformed to determine the mass and velocity regimes at which perfect bouncingdoes occur and those where there is a chance of the aggregates stickingtogether. We conducted a microgravity experiment, which allows us toinvestigate free collisions of millimeter-sized SiO2 dust aggregates at therelevant velocities. We analyzed 52 collisions in detail with velocities of 3.4mm/s to 6.2 cm/s and found four of them leading to sticking, while the otheraggregates rebounded. Three out of the four sticking collisions occurred atvelocities where previously only bouncing had been predicted. Although theprobability for sticking is low, this opens a new possibility for growth beyondmillimeter sizes. Our setup allowed us to obtain the complete three-dimensionalcollision information. Since most previous experiments were interpreted basedon two-dimensional information, we compare our three-dimensional values withthose obtained if only one projection had been available. We find that theerror of a two-dimensional analysis of the collision velocity is very small.The distribution of the coefficient of restitution in the two-dimensional viewis representative of the real case, but for any given collision its value canbe far off. Impact parameters always have to be analyzed three-dimensionally,because the two-dimensional values are not meaningful in any way.

Free Collisions in a Microgravity Many-Particle Experiment. IV. - Three-Dimensional Analysis of Collision Properties