6
Width of
Main Sequence – and Stellar Aging
•As
star converts H to He you have more massive nuclei
–Pressure
related to number of nuclei
–Gravity
related to mass of nuclei
•Pressure
would tend to drop unless something else happens
•Temperature
must rise (slightly) to
compensate
•Luminosity must rise (slightly) as heat leaks out faster
From our text: Horizons, by Sees