Talk:Stellar nucleosynthesis

To-do list

Just to remember some of the missing bits:

• agreement with observation
  • elements aboundance
  • luminosity of star
• what's up with very small and very massive stars
• solar neutrino & solar neutrino problem
• link to stellar evolution
• ref to Helium flash
• Supernova nucleosynthesis (TODO)
• Big bang nucleosynthesis (too expand, lot to say!)
• Nucleosynthesis (stubby, to expand)
• should be better to merge most of this: easy to make comparison/odd Z/double odd Z/magic number/...
• CN cycle in CNO cycle
• Carbon burning process, Oxygen burning process, Silicon burning process are just drafts

-- Looxix 01:25 Apr 28, 2003 (UTC)

And the magnesium-burning process(es).32ieww (talk) 03:22, 10 February 2017 (UTC)

examples of observations that falsify stellar fusion models

FG Sagittae - variable star brightened four magnitudes while COOLING and shifting from UV to visible light, then dropped SEVEN magnitudes in less than a hundred years, it's moved all the way across "HR diagram", and now it's a binary pair - impossible to explain by common belief systems involving stars radiating heat from nucleosynthesis, exactly what electric models would predict as a star is subjected to violent change in current density; fission of the star and as a result lower current density on the surface of the (now) two bodies

other variable stars defying faith-based stellar fusion beliefs: V 605 Aquilae (similar to above), V 4334 Sagittarii (changed both spectral type and observed composition in years), V838 Monocerotis (changed from an apparently small star hotter than the sun to a cooler "giant" star in a matter of months, defying ANY explanation by stellar fusion models)

If stellar fusion models were valid these types of changes might have an outside chance of taking place in a few thousand years, but typically it would be on the order of a few HUNDRED THOUSAND YEARS. How much evidence is required to falsify a hypothesis? Here's a clue: any

This stellar fusion article should be labelled pseudoscience, because observations falsify it, yet it persists as a belief system. Either pseudoscience or religion, either would be okay.

I was wondering

is there anything that a nineth grade science student could do for a science fair, that is in two days? We had learned that different elements burn into different colors and are there any household items that can be burnt that will not be dangerous to anyone? Tank you, Arden Portis —The preceding unsigned comment was added by 65.73.179.110 (talk) 23:03, 17 April 2007 (UTC).

WikiProject class rating

This article was automatically assessed because at least one WikiProject had rated the article as start, and the rating on other projects was brought up to start class. BetacommandBot 10:04, 10 November 2007 (UTC)

elements created during stellar necleosynthesis

In the wikipage for Iron_peak, it states that the elements lighter than Iron are created in stellar nucleosynthesis. Is this what you mean when you say that stellar nucleosynthesis creates the nuclei for heavier elements? Rhetth (talk) 03:41, 10 January 2008 (UTC)

Photon creation

I don't know, but I have seen it on History Channel's Universe series; the photon creation (light creating) in stars from the reactions inside the star

Plus the time one photon takes to escape the star's core

Thanks —Preceding unsigned comment added by 82.201.181.249 (talk) 21:10, 17 March 2008 (UTC)

Eddington or Perrin?

The History section starts with In 1920, Arthur Eddington ... was the first to suggest that stars obtained their energy from nuclear fusion of hydrogen to form helium. However this article on Why the Stars Shine (see p.6-8) says that Eddington developed an initial suggestion by Jean Perrin in 1919. Dirac66 (talk) 02:38, 19 April 2013 (UTC)

Magnesium burning

I'm completely sure that magnesium is involved in a burning reaction of its own, I'm not sure what it is, so someone should create a page about it. I would love to be bold, but I can't due to this. 32ieww (talk) 03:18, 10 February 2017 (UTC) And what about sodium burning? How does it proceed? In the end, I just want to see how Ne21,22, Na23, Si29,30, S33,34, Ar38, K39,41, Ca42, and any other products from the carbon and oxygen burning products. However, I have found the answer to the "magnesium mystery." Mg24+He4=Si28. 32ieww (talk) 01:17, 24 February 2017 (UTC)

Beyond Carbon, created by the triple-alpha process, heavier elements are largely created in the core by alpha capture. Thus the predominant elements in evolved stars are Oxygen, Neon, Magnesium, etc, with the intervening odd-number elements created in smaller quantities by less common reactions. There is a list of most of the relevant reactions, which usually have their own articles, but some description in this article would be helpful. Lithopsian (talk) 15:09, 24 February 2017 (UTC)

Nucleosynthesis of the most common elements

	1H 2D
		H	+	H	=	D
		D	+	D	=	He
	4He
		He	+	He	=	Unstable
		He	×	3	=	C
		He	+	C	=	O
	12C
		C	+	C	=	Mg
		C	+	O	=	Si
	16O
		O	+	O	=	S
		O	+	Mg	=	Ca
	24Mg
		Mg	+	S	=	Fe
	28Si 32S
		Si	+	Si	=	Fe
	56Fe
N and Ne are produced when the outer layers of the star become convective.

Just granpa (talk) 18:14, 15 July 2018 (UTC)

The first work of stellar nucleosynthesis?

The history section of the article asserts that Hoyle's 1954 papers was the "first work of stellar nucleosynthesis". I don't doubt that it was important, but this assertion of "first" comes after several paragraphs discussing earlier work on stellar nucleosynthesis, though that work was for lighter elements. Anyway, it appears to me that the description of Hoyle's work needs to be nuanced. Attic Salt (talk) 14:17, 18 July 2019 (UTC)

That sentence was added here during a series of edits which pushed a fairly focused point of view, and a definition of "stellar nucleosynthesis" that is no longer expressed in the opening sentence, and were in large part reverted or modified later. The nuance would be a definition of stellar nucleosynthesis as a theory to explain the abundance of the elements and "first work" as the earliest cohesive attempt to do that. Hoyle's earlier work didn't really attempt to do that, only to explain that (many) heavy elements could be produced in stars (and supernovae). The papers prior to that are focused on the energy production in main sequence stars, and so incidentally on the production of helium, and even more incidentally of carbon, nitrogen, and oxygen. Lithopsian (talk) 15:44, 18 July 2019 (UTC)

I removed that sentence and another one that I couldn't figure out how to fix. Attic Salt (talk) 18:50, 18 July 2019 (UTC)

Still seems to need heavy copyedit. I took a look at nucleosynthesis, sort of the parent article which I'd not really paid any attention to before. It is in better shape than this or supernova nucleosynthesis, but I still ended up doing significant work on the lead. Probably should have looked at the rest of the article first and them summarised it in the lead! Lithopsian (talk) 12:28, 19 July 2019 (UTC)

Yes, this article needs quite a bit of work. The history section is confusing on subject of Hoyle. Clear distinction between "normal" nucleosynthesis and supernova nucleosynthesis is needed -- in my interpretation (and that is all that it is), supernova nucleosynthesis is a subset of stellar nucleosynthesis. Attic Salt (talk) 12:37, 19 July 2019 (UTC)

Whatever definition we run with here and in supernova nucleosynthesis should be reflected in nucleosynthesis. Explicitly, since that article covers both of them. Currently, they are treated as essentially separate processes in nucleosynthesis, although bear in mind such terms as explosive nucleosynthesis which blur the boundaries - or perhaps which offer a different way to set the boundaries. Possibly we should support the definitions better with references. Also, at the risk of introducing confusion, we might discuss different historical slants; when stellar nucleosynthesis was first introduced as a thing, it was a proposed theory to explain the creation of the elements, whereas now we tend to treat it as a given, a process that is actually happening. Similarly, supernova nucleosynthesis was first introduced as a slight extension to stellar nucleosynthesis when it wasn't even really understood what a supernova was. Now it is a given, a process to be explained and quantified. Anyway, can't go wrong with references to what a few books say they are. Lithopsian (talk) 14:20, 19 July 2019 (UTC)

Stellar Nucleosynthesis consists of both Fusion and Fission reactions

I was prompted to edit this page by a Jeopardy question: “This process creates elements in stars.” The correct response was “What is nuclear fusion?”

That is not technically correct. There are many elements that are produced in stars by fission, not fusion.

For example, stable iron is created by the decay of unstable nickel. This is a fission reaction, not a fusion reaction.

Look at the b2fh paper. Many of the reactions in the paper are fission reactions. The diagram on page 552 specifically references fission reactions.

The CNO cycle itself has fission as part of the process. Otherwise, there would be no cycle. Without fission, you can not get back to Carbon after you have reached Oxygen in the process. — Preceding unsigned comment added by Bartosik (talk • contribs) 21:42, 15 December 2019 (UTC)

Careful now. Most definitions of nuclear fission specifically exclude well-defined processes such as alpha decay or beta decay. If you want to refer to fission in this context, you should explain what it is in the body of the article, with reliable external references, then summarise it in the lead. Slamming the words into the lead with no specific reference and no mention in the body is just asking for those edits to be reverted, whether they're accurate or not. You might want to consider whether r-process production of heavy elements that can undergo true fission is or should be discussed under this title. Lithopsian (talk) 14:49, 16 December 2019 (UTC)

I would like to see the effect of both fission and decay on Nucleosyntesis. If that doesn't happen I would like to see references to why that doesn't happen.

Certainly on earth decay is a significant source of Helium. So what is the scope of this article? Is it how elements get created (which the chart would seem to indicate) or is it the theory of how a subset of those elements get created by only stellar nucleosynthesis?

It would certainly make sense to me for the large merges to become the "scaffolding" of element creation. But a star is a neutron rich environment and I would expect some captures of neutrons. I'm not a physicist, but my physics classes would suggest that in the case of a neutron capture different elements could be obtained by either fission (for the heavier elements) and more importantly some kind of beta decay where a lighter element can capture a neutron and create a new element. If we can synthesize elements on earth with this process, why can stars - a much bigger reactor - perform the same synthesis? — Preceding unsigned comment added by 136.37.147.75 (talk) 14:37, 1 October 2021 (UTC)

catastrophic

"a higher–mass star will eject mass via a sudden catastrophic event called a supernova." Please someone remove "catastrophic", before I replace it with "wonderful" ... or "life giving and star formation inducing". Darsie42 (talk) 19:07, 8 August 2022 (UTC)

Burning?

All through the first part of this entry, the term "burning" is used. That's really not right. 'Burning' specifically refers to combustion with oxygen. Shouldn't this be referring to fusion instead? ...phil (talk) 17:07, 7 February 2024 (UTC)

Burning seems to be quite often used in the context of nuclear fusion, as you can verify in our article about it. The first dictionary I opened does not mention oxigen.

For the search string "nuclear fusion" burning I get 32200 hits with Google Scholar and 125000 with Google books - DVdm (talk) 18:25, 7 February 2024 (UTC)

Technetium on the Periodic Table

If I'm reading it correctly, the Periodic Table showing the origin of elements has an error: as it says in the Technetium Wikipedia article --

Naturally occurring technetium is a spontaneous fission product in uranium ore and thorium ore (the most common source), or the product of neutron capture in molybdenum ores.

Yet the Table in this article appears to indicate that technetium is only produced artificially. Dismalscholar (talk) 22:23, 3 June 2024 (UTC)