<p>Yes, nebulae can often have very distinct colours. What produces those colours can depend on what elements are in the nebula material and what the temperature and density are.</p>

<p><em>Generally speaking</em>, green colours in a nebula are due to forbidden transitions in ionised Oxygen, though can feature the hydrogen <span class="math-container">$\beta$</span> Balmer line. Red colours can be due to Hydrogen <span class="math-container">$\alpha$</span>, but there are also lines due to ionised sulphur and nitrogen that often make contributions.</p>

<p>If you take a spectrum of a nebula it usually completely obvious what elements are responsible, because the spectra consist of very sharp emission lines at the wavelengths that correspond to the well-known electronic transitions in particular species. An example is shown below, which is the spectrum of a typical planetary nebula.
Here, the labels mean the following: OIII means oxygen with its outer two electrons removed; NII is nitrogen with its outer electron removed etc., H<span class="math-container">$\alpha$</span>, <span class="math-container">$\beta$</span>, <span class="math-container">$\gamma$</span> are the <span class="math-container">$n=3 \rightarrow 2$</span>, <span class="math-container">$n=4 \rightarrow 2$</span> and <span class="math-container">$n=5 \rightarrow 2$</span> transition of the hydrogen Balmer series. The wavelength scale is in angstroms where 10 angstroms is 1 nm. So 5000 angstroms is the green part of the spectrum, 6500 angstroms is red and 4000 angstroms is blue.</p>

<p><a href="https://i.sstatic.net/KYZSC.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/KYZSC.png" alt="Typical spectrum of a planetary nebula"></a></p>

CC BY-SA 4.0
2020-01-23T15:54:24.823Z
2020-01-23T15:54:24.823Z
ProfRob
<p>A Nebula has bright awesome colors that include red, blue, green, orange, white, etc?</p>

<p>They're result of excitation of electrons. </p>

<p>Is there a clear explanation as to which color is attributed to an atom for Color properties in Cosmos!?</p>

<spectroscopy><spectra><nebula>
Nebula and its colors
Pranay
# Nebula and its colors

(Asked by: username_0 on 2020-01-22)

A Nebula has bright awesome colors that include red, blue, green, orange, white, etc?

They're result of excitation of electrons.

Is there a clear explanation as to which color is attributed to an atom for Color properties in Cosmos!?

**Tags:** spectroscopy, spectra, nebula

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## 1 answers

### Answer by username_1 on 2020-01-23. Score: 4

Yes, nebulae can often have very distinct colours. What produces those colours can depend on what elements are in the nebula material and what the temperature and density are.

*Generally speaking*, green colours in a nebula are due to forbidden transitions in ionised Oxygen, though can feature the hydrogen $\beta$ Balmer line. Red colours can be due to Hydrogen $\alpha$, but there are also lines due to ionised sulphur and nitrogen that often make contributions.

If you take a spectrum of a nebula it usually completely obvious what elements are responsible, because the spectra consist of very sharp emission lines at the wavelengths that correspond to the well-known electronic transitions in particular species. An example is shown below, which is the spectrum of a typical planetary nebula.
Here, the labels mean the following: OIII means oxygen with its outer two electrons removed; NII is nitrogen with its outer electron removed etc., H$\alpha$, $\beta$, $\gamma$ are the $n=3 \rightarrow 2$, $n=4 \rightarrow 2$ and $n=5 \rightarrow 2$ transition of the hydrogen Balmer series. The wavelength scale is in angstroms where 10 angstroms is 1 nm. So 5000 angstroms is the green part of the spectrum, 6500 angstroms is red and 4000 angstroms is blue.

[![Typical spectrum of a planetary nebula](https://i.sstatic.net/KYZSC.png)](https://i.sstatic.net/KYZSC.png)


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