Timeline for The sun "burns" hydrogen and even has "campfires" on it, but has anyone calculated a rate of actual chemical burning on the Sun?
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12 events
| when toggle format | what | by | license | comment | |
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| May 23, 2021 at 12:53 | answer | added | fraxinus | timeline score: 2 | |
| May 23, 2021 at 3:00 | history | tweeted | twitter.com/StackAstronomy/status/1396300012091592707 | ||
| May 22, 2021 at 10:11 | comment | added | PM 2Ring | @PeterErwin Ah, right. That's what I meant to imply in part 2 of my 1st comment. (Oops). As I said in part 1, it's certainly far too hot near the core for atoms to be combined into molecules, what to speak of dust grains. | |
| May 22, 2021 at 10:02 | comment | added | Peter Erwin | @PM2Ring Yes, but the point is that it's the elemental constituents (e.g., C, O, Si, Fe) that eventually make up grains which are "dredged-up", not the actual dust grains or even their simple molecular precursors. Those are formed in the very outer atmosphere or in outflows and winds. (For one thing, the temperatures at the base of the convection zone are millions of K, while the evaporation temperature for dust grains is of order 1000 or 2000 K.) | |
| May 22, 2021 at 9:45 | comment | added | PM 2Ring | @PeterErwin From en.wikipedia.org/wiki/Dredge-up "By definition, during a dredge-up, a convection zone extends all the way from the star's surface down to the layers of material that have undergone fusion. Consequently, the fusion products are mixed into the outer layers of the star's atmosphere...". Some of the dredged up matter has been produced in the star, but some of it was produced by earlier stars. | |
| May 22, 2021 at 9:43 | comment | added | Alchimista | While I'd avoid the term combustion for several reasons, the section "Evidence and Research" of this Wikipedia article mention various oxides and water somewhere in/near the sun. en.m.wikipedia.org/wiki/Molecules_in_stars | |
| May 22, 2021 at 9:18 | comment | added | Peter Erwin | @PM2Ring I don't think it's correct to say that dust is "dredged up... by convection". "Dredge-up" refers to heavier nuclei formed by fusion reactions deeper in the star. The dust forms in the very outer part of the atmosphere (possibly for some carbon-rich grains) or in the outflowing stellar wind (for silicate grains). | |
| May 22, 2021 at 7:59 | comment | added | PM 2Ring | Note that I was very careful in my "hydrogen burning" answer to avoid saying that chemical reactions don't happen in stars. ;) | |
| May 22, 2021 at 7:51 | comment | added | uhoh | @PM2Ring "Arrrrr... there be chemistry in them thar starrrrrrs!" (spoken in 'pirate dialect') | |
| May 22, 2021 at 4:14 | comment | added | PM 2Ring | 1. Although atoms are separated & fully ionised deep inside the Sun, there are some molecules (eg carbon monoxide) in the upper layers. See aanda.org/articles/aa/abs/2007/06/aa6173-06/aa6173-06.html 2. Stellar dust is mostly emitted by red giants. It's dredged up at various stages, by convection. The metals in the dust can be primordial, but in larger stars they can be freshly produced. | |
| May 22, 2021 at 3:04 | history | edited | uhoh | CC BY-SA 4.0 |
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| May 22, 2021 at 2:49 | history | asked | uhoh | CC BY-SA 4.0 |