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Hayashi track(hÿ-ah -shee) A near-vertical downward-directed line on the Hertzsprung–Russell diagram that is believed to be followed by protostars as they contract toward the main sequence. C. Hayashi (1965) calculated these tracks as the evolutionary paths of stars that are convective throughout (see energy transport), as protostars are expected to be during at least their early contraction.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006
Hayashi track[ha′ya·shē ‚trak]
A vertical track on the Hertzsprung-Russell diagram along which a star of small mass descends during its early stages of formation, when convective heat transport prevails over most of the star.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.