<p>As a comment, after doing some digging myself, the term &quot;metal&quot; was common in work during the start of the analysis of solar spectra ~1850, see Part 2 of Meadows, A. J. (Arthur Jack) (1970). <em>Early solar physics</em>. Internet Archive. Oxford, New York, Pergamon Press. ISBN 978-0-08-006653-0. The explanation by <a href="https://astronomy.stackexchange.com/users/7411/peter-erwin">Peter Erwin</a> above seems to be a correct, but has a typo and should read <strong>1850</strong> not <strong>1950</strong>. Many authors in the collection by Meadows refer to the chemical composition as metals and H, with He added later. Kirchhoff is prominent in these papers, but there does not seem to be a &quot;smoking gun&quot; that is very specific, or at least I have not found one.</p>
<p>For rigor, none of the early works in Meadows book considers the sun to have the same chemical composition as the earth, maybe that came later.</p>

CC BY-SA 4.0
2024-07-17T12:33:05.217Z
My comment did not actually have a typo, because I meant the 1950s, not the 1850s.
Peter Erwin
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2024-07-18T22:04:23.583Z
The literature has useage in ~1850.
Laurence D Marks
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2024-07-16T10:17:32.023Z
2024-07-16T10:17:32.023Z
LDM
<p>This is an existing question with good answers at  <a href="https://astronomy.stackexchange.com/questions/2513/metallicity-of-celestial-objects-why-metal-non-metal">Metallicity of Celestial Objects: Why &quot;Metal = Non-metal&quot;?</a> , but one thing is missing in the answers: a specific source that states that it came from Kirchoff &amp; Bunsen. So far I have not found one, and quoting a stack exchange page won't work in a manuscript even if it is correct. Can one of the people who answered such as <a href="https://astronomy.stackexchange.com/users/1862/aaron">https://astronomy.stackexchange.com/users/1862/aaron</a> or <a href="https://astronomy.stackexchange.com/users/2531/profrob">https://astronomy.stackexchange.com/users/2531/profrob</a> perhaps respond.</p>

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2024-07-02T12:28:13.570Z
I don't think either answer you cite claims that Kirchoff and Bunsen invented the terminology.
ProfRob
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2024-07-02T13:34:47.747Z
Neither of those answers actually says the specific terminology came from Kirchoff or Bunsen. My impression, from some semi-casual literature searches on NASA ADS, is that the terminology emerged in the 1950s from analyses of the solar spectrum in the optical, where the absorption lines that aren't from H or He are overwhelmingly from (genuine) metals (esp. Na, Mg, Ca, Fe). So "metals" became a shorthand for "all the stuff that isn't H or He".
Peter Erwin
CC BY-SA 4.0
2024-07-02T13:37:40.423Z
Kirchoff and Bunsen died in 1880s - 1890s.  The term metals for elements heavier than Helium in the spectra of stars did not develop until the 1950s.  I don't think anyone actually coined it.  Population I and Pop II stars are metal poor and metal rich, respectively.  Lines indicating that a star is Pop  II were loosely called metal lines.
eshaya
CC BY-SA 4.0
2024-07-02T15:41:56.160Z
The "metals" terminology is less than a century old. Before [Cecilia Payne-Gaposchkin](https://en.wikipedia.org/wiki/Cecilia_Payne-Gaposchkin) proposed (in her 1925 doctoral thesis) that stars are composed primarily of hydrogen and helium, it was generally assumed that no significant elemental differences distinguished the Sun and Earth.
PM 2Ring
CC BY-SA 4.0
2024-07-15T05:59:59.583Z
I think this question (with some minor editing) might have more chance of good answers on our sibling site [History of Science & Mathematics](https://hsm.stackexchange.com/).
Chappo Hasn't Forgotten
<stellar-astrophysics><metallicity><metal>
Metallicity of Celestial Objects: Why "Metal = Non-metal" Source
Laurence D Marks
# Metallicity of Celestial Objects: Why "Metal = Non-metal" Source

(Asked by: username_0 on 2024-07-02)

This is an existing question with good answers at [Metallicity of Celestial Objects: Why "Metal = Non-metal"?](https://astronomy.stackexchange.com/questions/2513/metallicity-of-celestial-objects-why-metal-non-metal) , but one thing is missing in the answers: a specific source that states that it came from Kirchoff & Bunsen. So far I have not found one, and quoting a stack exchange page won't work in a manuscript even if it is correct. Can one of the people who answered such as <https://astronomy.stackexchange.com/users/1862/aaron> or <https://astronomy.stackexchange.com/users/2531/profrob> perhaps respond.

**Tags:** stellar-astrophysics, metallicity, metal
> **Comments:**
> **username_1**: I don't think either answer you cite claims that Kirchoff and Bunsen invented the terminology.  
> **username_2**: Neither of those answers actually says the specific terminology came from Kirchoff or Bunsen. My impression, from some semi-casual literature searches on NASA ADS, is that the terminology emerged in the 1950s from analyses of the solar spectrum in the optical, where the absorption lines that aren't from H or He are overwhelmingly from (genuine) metals (esp. Na, Mg, Ca, Fe). So "metals" became a shorthand for "all the stuff that isn't H or He".  
> **username_3**: Kirchoff and Bunsen died in 1880s - 1890s.  The term metals for elements heavier than Helium in the spectra of stars did not develop until the 1950s.  I don't think anyone actually coined it.  Population I and Pop II stars are metal poor and metal rich, respectively.  Lines indicating that a star is Pop  II were loosely called metal lines.  
> **username_4**: The "metals" terminology is less than a century old. Before [Cecilia Payne-Gaposchkin](https://en.wikipedia.org/wiki/Cecilia_Payne-Gaposchkin) proposed (in her 1925 doctoral thesis) that stars are composed primarily of hydrogen and helium, it was generally assumed that no significant elemental differences distinguished the Sun and Earth.  
> **username_5**: I think this question (with some minor editing) might have more chance of good answers on our sibling site [History of Science & Mathematics](https://hsm.stackexchange.com/).  

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## 1 answers

### Answer by username_6 on 2024-07-16. Score: 1

As a comment, after doing some digging myself, the term "metal" was common in work during the start of the analysis of solar spectra ~1850, see Part 2 of Meadows, A. J. (Arthur Jack) (1970). *Early solar physics*. Internet Archive. Oxford, New York, Pergamon Press. ISBN 978-0-08-006653-0. The explanation by [Peter Erwin](https://astronomy.stackexchange.com/users/7411/peter-erwin) above seems to be a correct, but has a typo and should read **1850** not **1950**. Many authors in the collection by Meadows refer to the chemical composition as metals and H, with He added later. Kirchhoff is prominent in these papers, but there does not seem to be a "smoking gun" that is very specific, or at least I have not found one.

For rigor, none of the early works in Meadows book considers the sun to have the same chemical composition as the earth, maybe that came later.

> **Comments:**
> **username_2**: My comment did not actually have a typo, because I meant the 1950s, not the 1850s.  
> **username_0**: The literature has useage in ~1850.  

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