Editing Metallicity (section)

==Metals in early spectroscopy==
[[Image:Fraunhofer lines.svg|thumb|upright=1.6|Solar spectrum with Fraunhofer lines as it appears visually.]]
In 1802, [[William Hyde Wollaston]]<ref name="eb">Melvyn C. Usselman: [http://www.britannica.com/EBchecked/topic/646649/William-Hyde-Wollaston William Hyde Wollaston] Encyclopædia Britannica, retrieved 31 March 2013</ref> noted the appearance of a number of dark features in the solar spectrum.<ref>William Hyde Wollaston (1802) [http://rstl.royalsocietypublishing.org/content/92/365.full.pdf+html "A method of examining refractive and dispersive powers, by prismatic reflection,"] ''Philosophical Transactions of the Royal Society'', '''92''': 365–380; see especially p. 378.</ref> In 1814, [[Joseph von Fraunhofer]] independently rediscovered the lines and began to systematically study and measure their [[wavelength]]s, and they are now called [[Fraunhofer lines]]. He mapped over 570 lines, designating the most prominent with the letters A through K and weaker lines with other letters.<ref>{{cite book|last=Hearnshaw|first=J.B.|title=The analysis of starlight|date=1986|publisher=[[Cambridge University Press]]|location=Cambridge|isbn=978-0-521-39916-6|page=27}}</ref><ref>Joseph Fraunhofer (1814 - 1815) [https://books.google.com/books?id=2-AAAAAAYAAJ&pg=PA203 "Bestimmung des Brechungs- und des Farben-Zerstreuungs - Vermögens verschiedener Glasarten, in Bezug auf die Vervollkommnung achromatischer Fernröhre"] (Determination of the refractive and color-dispersing power of different types of glass, in relation to the improvement of achromatic telescopes), ''Denkschriften der Königlichen Akademie der Wissenschaften zu München'' (Memoirs of the Royal Academy of Sciences in Munich), '''5''':  193–226; see especially pages 202–205 and the plate following page 226.</ref><ref>{{Cite book
  | last1 = Jenkins  | first1 = Francis A.
  | last2 = White   | first2 = Harvey E.
  | title = Fundamentals of Optics
  | url = https://archive.org/details/fundamentalsopti00jenk  | url-access = limited  | edition = 4th
  | publisher = [[McGraw-Hill]]
  | date = 1981
  | page = [https://archive.org/details/fundamentalsopti00jenk/page/n37 18]
  | isbn = 978-0-07-256191-3
  }}</ref>

About 45 years later, [[Gustav Kirchhoff]] and [[Robert Bunsen]]<ref>See:
*  Gustav Kirchhoff (1859) [https://books.google.com/books?id=CMgAAAAAYAAJ&pg=PA662"Ueber die Fraunhofer'schen Linien"] (On Fraunhofer's lines), ''Monatsbericht der Königlichen Preussische Akademie der Wissenschaften zu Berlin'' (Monthly report of the Royal Prussian Academy of Sciences in Berlin), 662–665.
*  Gustav Kirchhoff (1859) [https://books.google.com/books?id=uksDAAAAYAAJ&pg=RA1-PA251 "Ueber das Sonnenspektrum"] (On the sun's spectrum), ''Verhandlungen des naturhistorisch-medizinischen Vereins zu Heidelberg'' (Proceedings of the Natural History / Medical Association in Heidelberg), '''1''' (7) :  251–255.</ref> noticed that several Fraunhofer lines coincide with characteristic [[emission spectrum|emission lines]] identifies in the spectra of heated chemical elements.<ref>{{cite journal 
 |author= G. Kirchhoff
 |title=Ueber die Fraunhofer'schen Linien
 |journal=Annalen der Physik
 |volume=185 |issue=1 |pages=148–150 |date=1860
 |doi=10.1002/andp.18601850115|bibcode = 1860AnP...185..148K |url=https://zenodo.org/record/1423666
 }}</ref> They inferred that dark lines in the solar spectrum are caused by [[absorption (electromagnetic radiation)|absorption]] by [[chemical element]]s in the solar atmosphere.<ref>{{cite journal 
 |author= G. Kirchhoff
 |title=Ueber das Verhältniss zwischen dem Emissionsvermögen und dem Absorptionsvermögen der Körper für Wärme und Licht
 |trans-title=On the relation between the emissive power and the absorptive power of bodies towards heat and light 
 |journal=Annalen der Physik
 |volume=185 |issue=2 |pages=275–301 |date=1860
 |doi=10.1002/andp.18601850205|bibcode = 1860AnP...185..275K |url=https://zenodo.org/record/1423668|doi-access=free}}</ref>  Their observations<ref>{{Cite web |title=Kirchhoff and Bunsen on Spectroscopy |url=https://www.chemteam.info/Chem-History/Kirchhoff-Bunsen-1860.html |access-date=2024-07-02 |website=www.chemteam.info}}</ref> were in the visible range where the strongest lines come from metals such as sodium, potassium, and iron.<ref>{{Cite web |title=Spectrum analysis in its application to terrestrial substances and the physical constitution of the heavenly bodies : familiarly explained / by H. Schellen ... |url=https://hdl.handle.net/2027/hvd.hn3317?urlappend=%3Bseq=211 |access-date=2024-07-02 |website=HathiTrust | hdl=2027/hvd.hn3317?urlappend=%3Bseq=211 |language=en}}</ref> In the early work on the chemical composition of the sun the only elements that were detected in spectra were hydrogen and various metals,<ref name="Meadows">{{Cite book |last=Meadows |first=A. J. (Arthur Jack) |url=http://archive.org/details/earlysolarphysic0000mead |title=Early solar physics |date=1970 |publisher=Oxford, New York, Pergamon Press |others=Internet Archive |isbn=978-0-08-006653-0}}</ref>{{Rp|pages=23–24}} with the term ''metallic'' frequently used when describing them.<ref name="Meadows" />{{Rp|location=Part 2}} In contemporary usage in astronomy all the extra elements beyond just hydrogen and helium are termed metallic.