Primordial heating of asteroidal parent bodiesMost meteorites show evidence of thermal processing either because of metamorphic changes or as a result of melting and differentiation. Proposed mechanisms for supplying this energy generally rely upon short-lived radioisotopes or electrical induction, though accretion is sometimes mentioned, and more exotic models have been discussed. Interest in isotopic heating has been heightened by the discovery of Al-26 in Allende inclusions and also by the proposal that a lunar core and dynamo resulted from the radioactive decay of superheavy elements during the early solar system. Electrical induction as a heat source can be scaled to a broad range of solar system conditions, but corroborative evidence for these conditions is inconclusive. The accretion mechanism is probably not viable for the asteroidal and meteorite parent bodies, because the high kinetic energy requirement is inconsistent with the formation of the objects and their regoliths in the presence of a weak gravitational field.
Document ID
19800040420
Acquisition Source
Legacy CDMS
Document Type
Other - Collected Works
Authors
Sonett, C. P. (Arizona, University Tucson, Ariz., United States)
Reynolds, R. T. (NASA Ames Research Center Moffett Field, Calif., United States)