184 
The Evolution of the Stars [ch. vi 
It now appears that the diagram we used to discuss the course of stellar 
evolution in § 158 needs amendment. It was drawn on the supposition that 
high surface-temperature was associated with high luminosity, and it now 
appears that, except where fission enters into the problem, the exact reverse 
is the case. To represent the configurations of simple stars, the lines OB, OQ, 
etc., which represented stars at given surface-temperatures, must be replaced 
by bands of finite width representing white dwarfs, K- ring stars, £-ring stars, 
etc. And the white dwarf band must come lowest, in some position such as 
OB in fig. 15, followed in succession by bands representing K- ring, X-ring 
stars, etc.