The Role of Ferromagnetic Iron in Planetesimal Formation

铁是原行星盘中含量最丰富的元素之一。有充分的证据表明，在行星形成的早期阶段也存在金属铁。由于普遍认为行星的形成始于尘埃颗粒的聚集，所以问题是铁在这一过程中扮演了什么角色。到目前为止，关于原行星盘内部区域的小行星形成的工作主要集中在硅酸盐的物理及其生长上。然而，最近的模型预测，铁颗粒可能会对生长过程产生强烈影响。当它们与磁盘的磁场相互作用时尤其如此。在本项目中，将首次在实验中研究不同金属-硅酸盐混合物在相对强度的磁场中以超过碎裂极限的速度碰撞时的演化。作为极端情况，这一过程将导致局部和成分选择性地启动小行星的形成。

Iron is among the most abundant elements in protoplanetary disks. There is ample evidence that also metallic iron is present during early phases of planet formation. Since it is generally accepted that planet formation starts with the aggregation of dust particles, the question is which role iron plays during this process. So far, work on planetesimal formation in the inner regions of protoplanetary disks concentrated on the physics of silicates and their growth. However, recent models predict that iron particles might have a strong influence on the growth process. This is especially true as they interact with the magnetic field of the disks. In this project the evolution of different metal-silicate mixtures in magnetic fields of relevant strengths colliding with velocities beyond the fragmentation limit will be studied in experiments for the first time. As extreme scenario, this process will lead to a local and compositional selective initiation of planetesimal formation.