Evidence for a Dynamo in the Main Group Pallasite Parent Body

Abstract

Magnetic Pallasites The origin of pallasite meteorites seems to defy explanation because their main constituents—iron and olivine—should have segregated into layers inside their parent body. The generally accepted model suggests that they formed at the coremantle boundary of an asteroid. Tarduno et al. (p. 939 ; see the Perspective by Weiss ) measured a remnant magnetization in olivine crystals of two pallasite meteorites and conclude that a dynamo must have operated in their parent body, providing further evidence that some asteroids were capable of dynamo generation. The data, together with thermal modeling, suggest that some pallasites could have formed when liquid FeNi from the core of an impacting asteroid was injected into the mantle of a large protoplanet.