Abstract：
:Chondrules are millimetre-sized spherules (mostly silicate) that dominate the texture of primitive meteorites. Their formation mechanism is debated, but their sheer abundance suggests that the mechanism was both energetic and ubiquitous in the early inner Solar System. The processes suggested--such as shock waves, solar flares or nebula lightning--operate on different length scales that have been hard to relate directly to chondrule properties. Chondrules are depleted in volatile elements, but surprisingly they show little evidence for the associated loss of lighter isotopes one would expect. Here we report a model in which molten chondrules come to equilibrium with the gas that was evaporated from other chondrules, and which explains the observations in a natural way. The regions within which the chondrules formed must have been larger than 150-6,000 km in radius, and must have had a precursor number density of at least 10 m(-3). These constraints probably exclude nebula lightning, and also make formation far from the nebula midplane problematic. The wide range of chondrule compositions may be the result of different combinations of the local concentrations of precursors and the local abundance of water ice or vapour.
journal_name
Naturejournal_title
Natureauthors
Cuzzi JN,Alexander CMdoi
10.1038/nature04834subject
Has Abstractpub_date
2006-05-25 00:00:00pages
483-5issue
7092eissn
0028-0836issn
1476-4687pii
nature04834journal_volume
441pub_type
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