Improving collision models of dust aggregates with MEDEA
René Weidling
Institute for Geophysics and extraterrestrial Physics Braunschweig, Germany
| The current paradigm of planet formation states that planetesimals form in disks of gas and dust, the so-called protoplanetary disks. However, how these bodies form from the initially only micrometer-sized dust particles is unknown. Growth simulations of dust particles in a protoplanetary disk making use of recent laboratory results found that the largest particles were only about one millimeter in size and further growth was prevented due to bouncing. In order to investigate the transition between bouncing and sticking collisions experimentally, we built a microgravity experiment (MEDEA) that allows us to investigate collisions of millimeter-sized, porous dust particles at velocities of ~ 1 mm/s. The results of the collisions are used to update our model. Additionally, a 3D optics allows us to calculate the impact parameter of the collisions and, thus, get statistics for the coefficient of restitution versus the collision velocity for central to grazing collisions. Together with measurements of the collision time, the results are used to develop an analytical collision model for these particles. The model is then compared to classical collision models of spheres (e.g. JKR theory) and is used to infer physical properties of the dust aggregates. |
|
Collaborators: C. Güttler, DEPS/IGEP, Japan/Germany J. Blum, IGEP, Germany |
Link to a key reference: Weidling et al. 2012 |