Authors: Halil KIRBIYIK
Abstract: In this study the subject of rotation in stars and its effects have been considered. First the historical development of the subject is reviewed. After discussing the observational aspects of rotation, the effect of rotation on evolution has been investigated. The velocity of rotational meridional circulation currents and related time scales were estimated. Mixing induced by circulation currents and the turbulence which may appear as a result of such a mixing have been studied. Order of magnitude calculations have shown that rotational mixing may occur in early type stars and thus contributes to the diffusion of chemical elements. Thus, it is argued that such a rotational mixing can explain the abnormal abundances observed in the atmospheres of OBN stars. In addition, it has been concluded that the same argument may be extended to explain the observed abundances in the atmosphere of Supernova 1987A.
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