Editing Yellow (section)

=== Astronomy ===
{{See also|Astronomy|Yellow supergiant|Cepheid variable}}

[[Star]]s of [[Stellar classification|spectral class]]es F and G have [[color temperature]]s that make them look "yellowish".<ref>{{cite book
| title = Stars and Galaxies
| first = Ron
| last = Miller
| publisher = Twenty-First Century Books
| year = 2005
| isbn = 978-0-7613-3466-8
| page = 22
| url = https://books.google.com/books?id=QL9uAfad1ggC&q=spectral-class+yellow&pg=PA22
| access-date = 23 November 2020
| archive-date = 20 March 2023
| archive-url = https://web.archive.org/web/20230320151550/https://books.google.com/books?id=QL9uAfad1ggC&q=spectral-class+yellow&pg=PA22
| url-status = live
}}</ref> The first astronomer to classify stars according to their color was [[Friedrich Georg Wilhelm von Struve|F. G. W. Struve]] in 1827. One of his classifications was {{lang|la|flavae}}, or yellow, and this roughly corresponded to stars in the modern spectral range F5 to K0.<ref>{{cite book | first=Paul | last=Murdin | year=1984 | page=[https://archive.org/details/coloursofstars0000mali/page/18 18] | title=Colours of the stars | publisher=CUP Archive | isbn=978-0-521-25714-5 | url=https://archive.org/details/coloursofstars0000mali/page/18 }}</ref> The [[Strömgren photometric system]] for stellar classification includes a 'y' or yellow filter that is centered at a wavelength of 550&nbsp;nm and has a bandwidth of 20–30&nbsp;nm.<ref>{{cite journal
| last=Strömgren | first=Bengt
| title=Main Sequence Stars, Problems of Internal Constitution and Kinematics (George Darwin Lecture)
| journal=Quarterly Journal of the Royal Astronomical Society | volume=8 | pages=8–37 | bibcode=1963QJRAS...4....8S
| year=1963
}}</ref><ref>{{Cite book
| last1 = Norton | first1 = Andrew | last2 = Cooper | first2 = W. Alan
| title=Observing the universe: a guide to observational astronomy and planetary science
| year=2004
| isbn=978-0-521-60393-5 | page=63 | publisher = Cambridge University Press | bibcode = 2004ougo.book.....N }}</ref>

[[Supergiant]] stars are rarely [[Yellow supergiant|yellow supergiants]] because F and G class supergiants are physically unstable; they are most often a transitional phase between [[blue supergiants]] and [[Red supergiant|red supergiants]]. Some yellow supergiants, the [[Cepheid variables]], pulsate with a period proportional to their [[absolute magnitude]]; hence, if their [[apparent magnitude]] is known, the distance to them can be calculated with great precision.<ref>{{Cite journal |last=Parsons |first=S. B. |date=1971-04-01 |title=Effective Temperatures, Intrinsic Colours, and Surface Gravities of Yellow Supergiants and Cepheids |journal=Monthly Notices of the Royal Astronomical Society |language=en |volume=152 |issue=1 |pages=121–131 |doi=10.1093/mnras/152.1.121 |doi-access=free |issn=0035-8711}}</ref> Cepheid variables were hence used to determine distances within and beyond the [[Milky Way]] galaxy. The most famous example is the current North Pole star, [[Polaris]].