Death of small stars

Planetary nebulae

In a low mass star in its last stage, with a helium burning shell, stellar modelling suggests that the helium burning shell becomes unstable, and burns in bursts. This causes the star to eject much of its outer layers.

The result is a ``planetary nebula'' which may last for 50,000 years before it dissapates into space.

Here is some evidence. (Colors in general aren't exactly real in these pictures.)

Left behind in the middle is a white dwarf star.

Type Ia supernovae

There are observed very violent explosions called supernovae. It appears that one kind of supernova is induced when extra mass from a companion star falls onto a white dwarf. The carbon core gets hot enough to begin fusion reactions, and does so explosively. It is like a huge nuclear bomb.

Davison E. Soper, Institute of Theoretical Science, University of Oregon, Eugene OR 97403 USA