'''Matahari''' atau '''Surya''' adalah [[bintang]] di pusat [[Tata Surya|tata surya]]
[[Tata Surya|surya]]. Bentuknya nyaris bulat dan terdiri dari plasma panas bercampur [[medan magnet]].<ref>{{cite news|url=http://science.nasa.gov/science-news/science-at-nasa/2008/02oct_oblatesun/|title=How Round is the Sun?|publisher=NASA|date=2 October 2008|accessdate=7 March 2011}}</ref><ref>{{cite news|url=http://science.nasa.gov/science-news/science-at-nasa/2011/06feb_fullsun/|title=First Ever STEREO Images of the Entire Sun|publisher=NASA|date=6 February 2011|accessdate=7 March 2011}}</ref> Diameternya sekitar 1.392.684 km,<ref name="arxiv1203_4898">{{citation |first1=Marcelo |last1=Emilio |first2=Jeff R. |last2=Kuhn |first3=Rock I. |last3=Bush |first4=Isabelle F. |last4=Scholl |title=Measuring the Solar Radius from Space during the 2003 and 2006 Mercury Transits |work=arXiv |url=http://arxiv.org/abs/1203.4898 |accessdate=2012-03-28}}</ref> kira-kira 109 kali diameter [[Bumi]], dan massanya (sekitar 2{{e|30}} kilogram, 330.000 kali massa Bumi) mewakili kurang lebih 99,86 % massa total tata surya. Matahari merupakan benda langit terbesar di galaksi [[Bima Sakti]] yang besarnya bahkan 10 kali planet terbesar tata surya, [[Jupiter]].<ref name="Woolfson00">
{{Cite journal
|last = Woolfson|first = M
|year = 2000
|title = The origin and evolution of the solar system
|journal = [[Astronomy & Geophysics]]
|volume = 41
|issue = 1 |pages=1.12
|doi = 10.1046/j.1468-4004.2000.00012.x
|ref = harv
}}</ref>
Secara kimiawi, sekitar tiga perempat massa matahari terdiri dari [[hidrogen]], sedangkan sisanya didominasi [[helium]]. Sisa massa tersebut (1,69%, setara dengan 5.629 kali massa Bumi) terdiri dari elemen-elemen berat seperti [[oksigen]], [[karbon]], [[neon]], dan [[besi]].<ref name=basu2008>
