Talk:Main sequence

Mistake in nuclear fusion for upper and lower main sequence stars

In the article about the main sequence it states this:

"Stars get the energy they produce through nuclear fusion of hydrogen into helium. The upper main sequence (hot and bright with the most mass) produces energy by one type of nuclear fusion involving only hydrogen and helium. The lower main sequence (cooler and less bright with a lower mass) produces energy by another type of nuclear fusion. This type uses other elements (for example, carbon, nitrogen and oxygen) with higher atomic numbers as nuclear catalysts."

This is the wrong way around. The so called CNO cycle, which is a way of fusing hydrogen into helium using some elements with a higher atomic number, is more efficient as the temperature goes up. High mass stars (the upper - main sequence stars) have a hotter core and are therefore the ones using this cycle to fuse hydrogen into helium. The lower mass stars have less hot cores (in comparison) and therefore will not use this method of fusion (or at least the most amount of fusion will not occur via this way). These lower mass stars use the so called proton-proton chain (or p-p chain) to fuse hydrogen to helium. So, the statement that I quoted above should be the other way around. On this wikipedia page it is in the right order: https://en.wikipedia.org/wiki/Proton–proton_chain

Cheers,

Jeroen (astronomy PhD student) 2001:770:60:CE:118E:77B2:7F88:32C0 (talk) 11:56, 18 November 2024 (UTC)[reply]

I think I've fixed these, please verify that it's correct if you're still around. Depextual (talk) 21:45, 5 December 2024 (UTC)[reply]