Does the Sun generate most of its energy using the CNO fusion cycle?
3 Answers
No.
Explanation:
Since its beginning our sun is comprised of hydrogen and helium. At the end of its life, after its red giant stage, it may produce a few elements including carbon and nitrogen but that will only happen at the end of the sun's life.
No, The Carbon-Nitrogen-Oxygen (CNO cycle) is the dominant method of nuclear fusion in stars more than 1.3 times as massive as the sun.
Explanation:
The Carbon-Nitrogen-Oxygen (CNO cycle) is the dominant method of nuclear fusion in stars that are more than 1.3 times as massive as the sun.
This is because, the temperature required for a self-sustained CNO cycle is mostly found in such massive stars.
In stars like the sun, The CNO cycle contributes to only about 1.7% of the Helium molecules generated.
For further reading:
CNO cycle
Our Sun, unlike larger stars, only produces about 10% of its output from the CNO cycle.
Explanation:
Main sequence stars, like our Sun, are fusing Hydrogen into Helium-4 in their cores. There are two principle Hydrogen to Helium-4 fusion reactions, the proton-proton chain and the Carbon-Nitrogen-Oxygen (CNO) cycle.
The proton-proton chain reaction is dominant in our Sun and stars smaller than about 1.3 solar masses. This reaction is Hydrogen
The CNO cycle uses Carbon as a catalyst. The Sun isn't hot enough to make this efficient so it only generates about 10% of its output from CNO. The CNO reaction is Carbon-12
The output of the CNO cycle increases with increasing temperature. The proton-proton chain reaction isn't so temperature sensitive. It is only in stars over 1.3 solar masses that the temperatures are high enough for the CNO cycle to dominate.