How Stars Make Energy and New Elements

Summary;

What do you really need to know about how stars make energy and
make new elements?

1) Stars make energy by converting matter into energy as they make
new elements by nuclear fusion – e.g. when 4 Hydrogen atoms are
combined to make 1 Helium atom 0.71% of the mass is converted
into energy. (and the Sun converts 4 million tons of matter into
energy each second)

2) There are more ways than one to combine Hydrogen into Helium
but it doesn’t matter which process we use: the energy yield is the
same! In the Sun and lower mass (i.e. cooler) stars the process is the
Proton-Proton chain. In more massive (i.e. hotter) stars, the
predominant process is the CNO cycle – although both processes
occur.

3) After stars run out of Hydrogen, they combine Helium into
heavier elements – and this is how many of the other elements are
made (Like Carbon, Nitrogen, Oxygen, Silicon, Iron, Sulfur, etc).
Many other elements are made by another process – but you have to
take Astro 10B to find out about that.