AS102 Study Guide - Final Guide: White Dwarf, Carbon-Burning Process, Planetary Nebula
Document Summary
This time, helium fusion begins around the carbon core. Meanwhile, the hydrogen furnace in the outer shell is still proceeding and the two shell layers (there was only one before) now begin to swell to an even greater size. It seems as if this process could go on forever, but at each cycle the temperature in the core must be progressively higher for the next level of fusion to start up. In this last case the only hope for the star is that carbon fusion will commence. However, temperatures in excess of 600 million k are needed for this to happen and the mass of the star is simply too small for this to ever happen. Finally, the star ejects its outer layers into space resulting in a huge shell of gas and dust expanding away from the hot carbon core that is emitting uv radiation.
