As far as I know, universe is electrically neutral so,
If stars are ionized, where are the electrons?
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$\begingroup$ Why do you think stars are ionized? The spectral lines come from excitations and deexcitations of atoms as they bump on each other. Due to the high temperatures this has high probability of happening. $\endgroup$– anna vOct 2, 2014 at 6:15
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$\begingroup$ Well, should I say "atoms in a star are ionized"? Maybe that's more correct. But still, if the star's atoms are ionized, I would assume the star it self is also ionized. Just my opinion. $\endgroup$– XtroOct 3, 2014 at 19:50
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$\begingroup$ Electrons and nuclei form a "soup" called plasma . en.wikipedia.org/wiki/Plasma_%28physics%29. Curiousone answer is correct . The electrons are there in the soup. Over all the star is neutral $\endgroup$– anna vOct 4, 2014 at 4:03
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2 Answers
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The electrons are still inside the stars. A stellar plasma is electrically (almost) neutral, the electrons in a plasma are simply not bound to individual nuclei. If we could take some plasma out of a star and we would let it cool down to room temperature, most of the matter in that gas (at least from main sequence stars) would be ordinary neutral hydrogen and helium gas.
answered Oct 2, 2014 at 7:05
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I learned that the electrons which are separated from their nuclei are being annihilated by the positrons. These positrons are the product of the weak interaction that emits photons from the sun.
So, the sun is producing photons by destroying the electrons (and of course, by converting protons into neutrons.
Source : https://www.youtube.com/watch?v=zS-LsjrJKPA&list=PL93B3DDC89C085C1C#t=827
Edit: Although the correct answer is the another one, I'll keep my answer here for the comments below this.
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$\begingroup$ Positrons are produced in fusion reactions, but that doesn't account for ionization of the star as a whole. $\endgroup$– David ZOct 2, 2014 at 21:54
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$\begingroup$ I didn't mean that production of positrons ionize the star. Star is ionized because of the heat as far as I know. I learned that these electrons (separated from the nuclei) is being annihilated by the positrons which are produced by weak interaction. $\endgroup$– XtroOct 3, 2014 at 18:35
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$\begingroup$ You must have heard of energy conservation and charge conservation? The positrons in our universe can only appear with charge conservation, for every positron there exists a negative charge to balance it, in our universe, concurrent with the generation of the positron, or it is just a product from a nuclear decay and the balance is given by the charges of the nuclei. There are very few positrons even in a very high energy plasma, and in any case for every created positron an electron is created concurrently. $\endgroup$– anna vOct 4, 2014 at 4:07
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$\begingroup$ An electron in a star plasma may meet a rare positron and annihilate, but the bulk of electrons that are separated from the nuclei ( hydrogen , helium nuclei) will not find a positron to annihilate into because the creation of e+e- pairs is rare. $\endgroup$– anna vOct 4, 2014 at 4:10