Cosmological lithium problem: Difference between revisions

Revision as of 02:28, 28 April 2022

Revision as of 22:43, 29 May 2022

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[[Image:SolarSystemAbundances.svg|thumb|center|800px|Abundances of the chemical elements in the Solar System. Hydrogen and helium are most common, residuals within the paradigm of the Big Bang.<ref>{{cite book |last1=Stiavelli |first1=M. |year=2009 |title=From First Light to Reionization the End of the Dark Ages |url=https://books.google.com/books?id=iCLNBElRTS4C&pg=PA8 |page=8 |publisher=[[Wiley-VCH]] |___location=Weinheim, Germany |isbn=9783527627370|bibcode=2009fflr.book.....S }}</ref> Li, Be and B are rare because they are poorly synthesized in the Big Bang and also in stars; the main source of these elements is [[cosmic ray spallation]].]]

Older stars seem to have less lithium than they should, and some younger stars have much more.<ref name="MWoo">{{cite web|title=The Cosmic Explosions That Made the Universe|url=http://www.bbc.com/earth/story/20170220-the-cosmic-explosions-that-made-the-universe|last=Woo|first=M.|date=21 Feb 2017|website=earth|publisher=BBC|url-status=live|archiveurl=https://web.archive.org/web/20170221214442/http://www.bbc.com/earth/story/20170220-the-cosmic-explosions-that-made-the-universe|archivedate=21 February 2017|access-date=21 Feb 2017|quote=A mysterious cosmic factory is producing lithium. Scientists are now getting closer at finding out where it comes from|df=dmy-all}}</ref> TheOne lackproposed ofmodel is that lithium inproduced olderduring starsa star's youth sinks beneath the star's atmosphere (where it is apparentlyobscured causedfrom bydirect observation) due to effects the authors describe as "turbulent mixing" ofand lithium"diffusion," intowhich theare interiorsuggested ofto stars,increase whereor itaccumulate isas destroyed,the star ages.<ref name=cld>{{Cite newsjournal |last=Richard |first=O. |last2=Michaud |first2=G. |last3=Richer |first3=J. |date=2005-01-20 |title=Implications of WMAP Observations on Li Abundance and Stellar Evolution Models |url=httphttps://wwwdoi.universetodayorg/10.com1086/476426470 |journal=The Astrophysical Journal |language=en |volume=619 |issue=1 |pages=538–548 |doi=10.1086/why-old426470 |issn=0004-637X}}</ref> Spectroscopic observations of stars in [[NGC 6397]], a metal-seem-to-lack-poor globular cluster, are consistent with an inverse relation between lithium/ abundance and age, but a theoretical mechanism for diffusion has not been formalized.<ref>{{Cite journal |titlelast=WhyKorn Old|first=A. StarsJ. Seem|last2=Grundahl to|first2=F. Lack|last3=Richard Lithium|first3=O. |datelast4=16Barklem August|first4=P. 2006S. |lastlast5=CainMashonkina |firstfirst5=FraserL. |urllast6=Collet |first6=R. |last7=Piskunov |first7=N. |last8=Gustafsson |first8=B. |date=2006-status08 |title=liveA probable stellar solution to the cosmological lithium discrepancy |archiveurlurl=https://web.archive.org/web/20160604044857/http://www.universetodaynature.com/476/why-old-stars-seem-to-lack-lithiumarticles/nature05011 |archivedatejournal=4Nature June|language=en 2016|volume=442 |dfissue=dmy-all7103 |pages=657–659 |doi=10.1038/nature05011 |issn=1476-4687}}</ref> while lithium is produced in younger stars. Though 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 current computations would predict in later-generation stars.<ref name=emsley/><ref name="Cain">{{cite web|url=http://www.universetoday.com/24593/brown-dwarf/|archiveurl=https://web.archive.org/web/20110225032434/http://www.universetoday.com/24593/brown-dwarf/|archivedate=25 February 2011|title=Brown Dwarf |accessdate=17 November 2009 |last=Cain |first=Fraser |publisher=Universe Today}}</ref>

[[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/|accessdate=29 July 2015|url-status=dead|archiveurl=https://web.archive.org/web/20150801001700/http://www.eso.org/public/news/eso1531/|archivedate=1 August 2015|df=dmy-all}}</ref>]]