Table 19-2:
How Helium Core Fusion Begins in Different Red Giants
Mass of star
Onset of helium fusion in core
More than about 0.4 but less than 2–3 solar masses
Explosive (helium flash)
More than 2–3 solar masses
Gradual
Stars with less than about 0.4 solar masses do not become red giants (see
Section 19-2
).