Particle Size Distributions Obtained Through Unfolding 2D Sections: Towards Accurate Distributions of Nebular Solids in the Allende Meteorite

摘要

Size distributions of nebular solids in chondrites suggest an efficient sorting of these early forming objects within the protoplanetary disk. The effect of this sorting has been documented by investigations of modal abundances of CAIs (e.g., (1-4)) and chondrules (e.g., (5-8)). Evidence for aerodynamic sorting in the disk is largely qualitative, and needs to be carefully assessed. It may be a way of concentrating these materials into planetesimal-mass clumps, perhaps 100 fs of ka after they formed. A key parameter is size/density distributions of particles (i.e., chondrules, CAIs, and metal grains), and in particular, whether the radius-density product (rxp) is a better metric for defining the distribution than r alone (9). There is no consensus between r versus rxp based models. Here we report our initial tests and preliminary results, which when expanded will be used to test the accuracy of current dynamical disk models.