CNO cycle

play
noun \ˌsē-ˌen-ˈō-\

Definition of CNO cycle

  1. :  the process by which large stars convert elemental hydrogen into helium through a series of nuclear fusion reactions To become a supernova, the progenitor star had to be at least eight times our Sun's mass, so it must have fused hydrogen into helium via the CNO cycle, a reaction that uses carbon, nitrogen, and oxygen as catalysts. — Wayne J. Parker, Sky & Telescope, January 1995 Stars that are roughly twice the size of the Sun or larger convert hydrogen by means of the CNO cycle, in which hydrogen nuclei combine with and then separate from carbon, nitrogen and oxygen in a specific repeating loop that generates both helium and extra energy. Smaller stars also fuse hydrogen into helium, but the process is different and does not involve other elements.

There's more!

Love words? You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!
Already a subscriber? Log in.

First Known Use of cno cycle

1958


Seen and Heard

What made you want to look up CNO cycle? Please tell us where you read or heard it (including the quote, if possible).

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

WORD OF THE DAY

clear to the understanding

Get Word of the Day daily email!

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!