Protostellar Winds and Chondritic Meteorites |
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Authors: | Hsien Shang Frank H Shu Typhoon Lee Alfred E Glassgold |
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Institution: | (1) Astronomy Department, University of California, Berkeley, CA 94720-3411, USA;(2) Institutes of Earth Sciences and Astronomy and Astrophysics, Academia Sinica, Nankang, Taipei, 115, TAIWAN;(3) Physics Department, New York University, New York, NY, 10003 |
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Abstract: | We discuss the interaction between the magnetosphere of a young star and its surrounding accretion disk. We consider how an
X-wind can be driven magnetocentrifugally from the inner edge of the disk where accreting gas is diverted onto stellar field
lines either to flow onto the Sun or to be flung outwards with the wind. The X-wind satisfies many observational tests concerning
optical jets, Herbig-Haro objects, and molecular outflows. Connections may exist between primitive solar system materials
and X-winds. Chondrules and calcium-aluminum-rich inclusions (CAIs) experienced short melting events uncharacteristic of the
asteroid belt where meteorites originate. The inner edge of the solar nebula has the shortest orbital timescale available
to the system, a few days. Protosolar flares introduce another timescale, tens of minutes to hours. CAIs may form when solids
are lifted from shaded portions of the disk close to the Sun and are exposed to its intense light for a day or so before they
are flung by the X-wind to much larger distances. Chondrules were melted, perhaps many times, by flares at larger distances
from the Sun before being launched and annealed, but not remelted, in the X-wind. Aerodynamic sorting explains the narrow
range of sizes with which CAIs and chondrules are found in chondritic meteorites. Flare-generated cosmic-rays may induce spallation
reactions that produce some of the short-lived radioactivities associated with primitive solar system rocks.
This revised version was published online in June 2006 with corrections to the Cover Date. |
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Keywords: | X-wind Young Stellar Objects Jets Chondrules CAIs Extinct Radioactivities |
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