Editing Lithium (section)

=== Astronomical ===
{{Main|Nucleosynthesis|Stellar nucleosynthesis|Lithium burning}}
Although it was synthesized in the [[Big Bang]], lithium (together with beryllium and boron) is markedly less abundant in the universe than other elements. This is a result of the comparatively low stellar temperatures necessary to destroy lithium, along with a lack of common processes to produce it.<ref name="wesleyan">{{cite web |url=http://www.astro.wesleyan.edu/~bill/courses/astr231/wes_only/element_abundances.pdf |archive-url=https://web.archive.org/web/20060901133923/http://www.astro.wesleyan.edu/~bill/courses/astr231/wes_only/element_abundances.pdf |archive-date=1 September 2006 |title=Element Abundances |access-date=17 November 2009}}</ref>

According to modern cosmological theory, lithium—in both stable isotopes (lithium-6 and lithium-7)—was one of the three elements synthesized in the Big Bang.<ref>{{cite journal |bibcode=1985ARA&A..23..319B |title=Big bang nucleosynthesis – Theories and observations |last1=Boesgaard |first1=A. M. |last2=Steigman |first2=G. |volume=23 |date=1985 |pages=319–378 |journal=Annual Review of Astronomy and Astrophysics |id=A86-14507 04–90 |location=Palo Alto, CA |doi=10.1146/annurev.aa.23.090185.001535}}</ref> Though the amount of lithium generated in [[Big Bang nucleosynthesis]] is dependent upon the number of [[photon]]s per [[baryon]], for accepted values the lithium abundance can be calculated, and there is a "[[cosmological lithium problem|cosmological lithium discrepancy]]" in the universe: older stars seem to have less lithium than they should, and some younger stars have much more.<ref>{{cite web |url=http://www.bbc.com/earth/story/20170220-the-cosmic-explosions-that-made-the-universe |title=The Cosmic Explosions That Made the Universe |last=Woo |first=Marcus |date=21 February 2017 |website=earth |publisher=BBC |access-date=21 February 2017 |quote=A mysterious cosmic factory is producing lithium. Scientists are now getting closer at finding out where it comes from |url-status=live |archive-url=https://web.archive.org/web/20170221214442/http://www.bbc.com/earth/story/20170220-the-cosmic-explosions-that-made-the-universe |archive-date=21 February 2017}}</ref> The lack of lithium in older stars is apparently caused by the "mixing" of lithium into the interior of stars, where it is destroyed,<ref name="cld">{{Cite news |url=http://www.universetoday.com/476/why-old-stars-seem-to-lack-lithium/ |title=Why Old Stars Seem to Lack Lithium |date=16 August 2006 |author=Cain, Fraser |url-status=live |archive-url=https://web.archive.org/web/20160604044857/http://www.universetoday.com/476/why-old-stars-seem-to-lack-lithium/ |archive-date=4 June 2016}}</ref> while lithium is produced in younger stars. Although it [[lithium burning|transmutes]] into two atoms of [[helium]] due to collision with a [[proton]] at temperatures above 2.4 million degrees Celsius (most stars easily attain this temperature in their interiors), lithium is more abundant than computations would predict in later-generation stars.<ref name="emsley" />
[[File:Nova Centauri 2013 ESO.jpg|thumb|[[Nova Centauri 2013]] is the first in which evidence of lithium has been found.<ref>{{cite web |title=First Detection of Lithium from an Exploding Star |url=http://www.eso.org/public/news/eso1531/ |access-date=29 July 2015 |url-status=live |archive-url=https://web.archive.org/web/20150801001700/http://www.eso.org/public/news/eso1531/ |archive-date=1 August 2015}}</ref>]]

Lithium is also found in [[brown dwarf]] substellar objects and certain anomalous orange stars. Because lithium is present in cooler, less-massive brown dwarfs, but is destroyed in hotter [[red dwarf]] stars, its presence in the stars' spectra can be used in the "lithium test" to differentiate the two, as both are smaller than the Sun.<ref name="emsley" /><ref>{{cite news |url=http://www.universetoday.com/24593/brown-dwarf/ |archive-url=https://web.archive.org/web/20110225032434/http://www.universetoday.com/24593/brown-dwarf/ |archive-date=25 February 2011 |title=Brown Dwarf |access-date=17 November 2009 |last=Cain |first=Fraser |work=Universe Today}}</ref><ref>{{cite web |url=http://www-int.stsci.edu/~inr/ldwarf3.html |archive-url=https://archive.today/20130521055905/http://www-int.stsci.edu/~inr/ldwarf3.html |archive-date=21 May 2013 |title=L Dwarf Classification |access-date=6 March 2013 |first=Neill |last=Reid |date=10 March 2002}}</ref> Certain orange stars can also contain a high concentration of lithium. Those orange stars found to have a higher than usual concentration of lithium (such as [[Centaurus X-4]]) orbit massive objects—neutron stars or black holes—whose gravity evidently pulls heavier lithium to the surface of a hydrogen-helium star, causing more lithium to be observed.<ref name="emsley" />

On 27 May 2020, astronomers reported that [[classical nova]] explosions are galactic producers of lithium-7.<ref name="EA-20200601">{{cite news |author=[[Arizona State University]] |title=Class of stellar explosions found to be galactic producers of lithium |url=https://www.eurekalert.org/pub_releases/2020-06/asu-cos060120.php |date=1 June 2020 |work=[[EurekAlert!]] |access-date=2 June 2020 |archive-date=3 June 2020 |archive-url=https://web.archive.org/web/20200603070318/https://www.eurekalert.org/pub_releases/2020-06/asu-cos060120.php |url-status=live}}</ref><ref name="AJ-20200527">{{cite journal |author1-link=Sumner Starrfield |author=Starrfield, Sumner |display-authors=et al. |title=Carbon–Oxygen Classical Novae Are Galactic 7Li Producers as well as Potential Supernova Ia Progenitors |date=27 May 2020 |journal=[[The Astrophysical Journal]] |volume=895 |number=1 |page=70 |doi=10.3847/1538-4357/ab8d23 |arxiv=1910.00575 |bibcode=2020ApJ...895...70S |s2cid=203610207 |doi-access=free}}</ref>