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The Planetoid-Impact Hypothesis of CP F, A, and B Star Formation: Possibilities and Perspectives

Published online by Cambridge University Press:  12 April 2016

E.M. Drobyshevski
E.M. Drobyshevski*
Affiliation:
A.F.Ioffe Physical-Technical InstituteAcademy of Sciences of the USSR 194021 Leningrad, USSR

Abstract

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A possibility is analyzed of explaining the chemical anomalies of chemically peculiar (CP) F-A-B stars basing on the assumption of the formation of a large number of moonlike planetoids both in the course of separation of the components and in late stages of close binary evolution.

Primitive igneous differentiation of such planetoids results in their crust becoming deficient in Mg, Ca, Sc and enriched in Pe, Sr, Ba, and the Rare Earths. Infall of such planetoids or crust fragments ejected in their collisions with one another onto an A star makes it Am-type. The deficiency of some elements relative to normal abundance can be accounted for if one assumes that these elements present in the matter streaming from one binary component to another condense with subsequent rain-out into a component or formation of the planetoids.

The more diverse and complex anomalies (including the separation of isotopes) can be explained in the same context of the close binary evolution by invoking the ideas of magnetic cosmochemistry which considers the consequences of extremely nonequilibrium processes associated with the flow of magnetic-field generated electrical currents through a rarefied matter in space.

Type
Section IV - Non-Magnetic CP and Related Stars
Information
International Astronomical Union Colloquium , Volume 90: Upper Main Sequence Stars with Anomalous Abundances , 1986 , pp. 473 - 476
Copyright
Copyright © Reidel 1986

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