Hayashi track

The Hayashi - line is an almost vertical line in the color-magnitude diagram, which areas in which stable hydrostatic equilibrium is possible, distinguishes itself from those where this is not possible. It is about an effective temperature of 4000 Kelvin, but their exact position depends on the mass of each star observed from the more mass, the higher the effective temperature at which the line is located. It was after Chushiro Hayashi ( * 1920, † 2010) named, who showed in 1961 that the right can not exist stable star of this line. Stars, which are located directly on the Hayashi - line, are vollkonvektiv and in hydrostatic equilibrium.

The Hayashi - line plays an important role in star formation. Looking at the development of the collapsing matter from which the star formed, in the color-magnitude diagram, so these approaches the Hayashi - line from the right. The collapse of the cloud is in free fall ends when reaching the Hayashi line. This date may therefore be regarded in a sense as the birth of the star. The further development of the star runs along the Hayashi - line down, that is, at constant surface temperature is reduced by the contraction of the surface and hence the luminosity, see also star formation.

Even with the evolution of stars in the post- main sequence phase, this line plays a role. Thus, giant stars, this line does not exceed and therefore their development in the color-magnitude diagram bends before reaching the Hayashi line to the top.