Laboratory Experiments on Preplanetary Dust Aggregation |
| |
Authors: | Jürgen Blum |
| |
Institution: | 1. Astrophysikalisches Institut und Universit?ts-Sternwarte, Friedrich Schiller-Universit?t Jena, D-07745, Jena, Germany
|
| |
Abstract: | For a better understanding of the processes which lead to the formation of planetesimals in the early solar nebula, we performed
an extensive series of laboratory experiments. We find that the capture velocities in collisions between spherical grains
are more than one order of magnitude higher than predicted by Chokshi et al (1993). In contrast, irregular grains have no
capture threshold and can be better described by a sticking probability which is typically a few 10%, even for velocities
exceeding 10 m/s. However, adhesion forces between spherical, micron-sized particles match the theoretical predictions very
well, although contact areas and deformations are of the order of inter-atomic distances only. Aggregation experiments in
rarefied turbulent gases reveal the fractal nature of dust aggregates. Mass distribution functions are bell-shaped. Similar
behaviour can be found in aggregation experiments with sedimenting particles. Experiments on collision-induced aggregate compaction
and fragmentation match the numerical simulations by Dominik and Tielens (1997) very well if revised experimental values of
the break-up energy (from our impact experiments) and the rolling-friction force (from our AFM measurements on particle chains)
are used.
This revised version was published online in June 2006 with corrections to the Cover Date. |
| |
Keywords: | Laboratory Experiments Preplanetery Dust Aggregation Planetesimal Formation |
本文献已被 SpringerLink 等数据库收录! |
|