Simulation of gas-grain collisions: a mechanism for chondrule formation

The exact process of chondrule formation is still not known. The most common scenarios are formation in a protoplanetary nebular environment: e.g. X-wind model [1] or nebular shock fronts, where precursor grains are heated by collisions with gas [2]. Most chondrules probably have been heated to 1500–1600 ºC, followed by a cooling rate of usually between 10 to 1000 ºC/h [3]. In this part of our study about the formation of chondrules by shock processes, we try to simulate the formation of chondrules by gas-grain collisions in a nebular environment. Earlier, related studies usually did not result in chondrulelike objects[4]. In a first series of experiments using plasma arcs, we produced successfully spherical silicate droplets in a simple set-up under atmospheric conditions. These chondrule-like objects already show similarities to actual chondrules [5]. In a second series, the experiments take place in an environment closer to the earlier solar nebula, at low pressure and a reducing environment