Professor Rhian Jones Chondrules and their importance in the early Solar System скачать в хорошем качестве

Professor Rhian Jones Chondrules and their importance in the early Solar System

Chondrules are millimetre-sized beads of rock that are common constituents of most chondrite meteorites. Their origins have been puzzling meteorite researchers for over 150 years. We know that chondrules formed in the earliest stages of Solar System history, in the presence of the protoplanetary disk. We also know that they formed in short heating events that produced large numbers of melt droplets, which then cooled quickly to form the solid chondrules we find in meteorites today. Chondrules are ubiquitous in chondrites that formed in both the inner and outer parts of the disk, although perhaps not in the furthest cold reaches of the dust cloud. Since it is likely that a large proportion of the disk’s dust was processed through chondrule-forming events, it is also likely that chondrules were an important building-block of rocky bodies, including asteroids, moons and planets. A fundamental problem is that we do not know the mechanism that heated chondrules, although many different possibilities have been suggested. The most plausible current explanation is that they were heated in shock fronts that passed through the disk, while impact events could also have been responsible. In this talk I will summarize some of the properties of chondrules that help us understand this important early stage of Solar System evolution and examine some of the outstanding questions that still evade explanations.