Why Do Nebulae only have Hydrogen, Oxygen and Sulfur?

[Newtons Apple]

TL;DR

Why Do Nebula only have Hydrogen, Oxygen and Sulfur?

So I love talking about space but I also hate rattling off misleading or wrong info...I'm trying to wrap my head around why the nebula we observe, only emit Hydrogen (of the alpha variety) Sulfur II and Oxygen III? Why these specific elements only? I do some astrophotography so these are the three color palette types that the RGB revolves around... but If the nebula is a planetary nebula, should it be an absolute cocktail of all of the elements that the star fused in the past? Or actually maybe just the last elements it was fusing? If a star burned through it's hydrogen supply millions of years ago, and is now fusing iron before it pops, why do the nebula then have the H, S and O ?

 

[Baluncore]

I'm trying to wrap my head around why the nebula we observe, only emit Hydrogen (of the alpha variety) Sulfur II and Oxygen III? Why these specific elements only?

That is hard to believe. Where does that restrictive H, S, & O emission analysis come from, a reference please?

Nebulae tend to have a continuous spectrum. Nebulae come in many forms. Most nebulae are not stars, they are vast star forming regions of dust and gas.

 

[Newtons Apple]

That is hard to believe. Where does that restrictive H, S, & O emission analysis come from, a reference please?

Nebulae tend to have a continuous spectrum. Nebulae come in many forms. Most nebulae are not stars, they are vast star forming regions of dust and gas.

So as I was waiting for a response I may be able to answer this myself... but let me run it by you and everyone... So I do a lot of astrophotography and we use filters to cut out a lot of the other light and only allow very specific bands from the spectrum to hit the camera. the issue is that whenever they discuss them, they ONLY discuss Oxygen, Sulfur and Hydrogen as if that's the only elements present. What I'm thinking is maybe those are the only ones that emit light when excited by the radiation from nearby stars?

 

[Tom.G]

Invoking some Google-Fu ---

http://www.google.com/search?hl=en&q=spectrum+of+Nebulae
Indicated that most nebula are around 90% H, with S and O making up most of the remaining 10%. Therefore, those are the three brightest emission lines.

Which led to:

https://www.cloudynights.com/topic/678744-nebula-emission-wavelength-chart/

which led to:

https://buil.astrosurf.com/nebula/nebula.html​

Cheers,
Tom

(Suggest you try it. You could get an almost infinite regression!)

 

[russ_watters]

Google('s"AI") tells me only about 10% of a star's hydrogen is fused in the main sequence. So, most other elements are pretty scarce. That doesn't beg the question though about why He isn't used much if at all. It probably has to do with the visibility of the emissions lines/spectrum.


Also note that planetary nubulae are from dissipated red giant, not supernova, so they dont get as much or wide variety of other elements.