Editing Binary star (section)

==Examples==
[[File:Albireo.jpg|thumb|The two visibly distinguishable components of [[Albireo]]]]

The large distance between the components, as well as their difference in color, make [[Albireo]] one of the easiest observable visual binaries. The brightest member, which is the third-brightest star in the [[constellation]] [[Cygnus (constellation)|Cygnus]], is actually a close binary itself. Also in the Cygnus constellation is [[Cygnus X-1]], an [[X-ray]] source considered to be a [[black hole]]. It is a [[high-mass X-ray binary]], with the optical counterpart being a [[variable star]].<ref>See sources at [[Cygnus X-1]]</ref> [[Sirius]] is another binary and the brightest star in the night time sky, with a visual [[apparent magnitude]] of −1.46. It is located in the constellation [[Canis Major]]. In 1844 [[Friedrich Bessel]] deduced that Sirius was a binary. In 1862 [[Alvan Graham Clark]] discovered the companion (Sirius B; the visible star is Sirius A). In 1915 astronomers at the [[Mount Wilson Observatory]] determined that Sirius B was a [[white dwarf]], the first to be discovered. In 2005, using the [[Hubble Space Telescope]], astronomers determined Sirius B to be {{convert|12000|km|0|abbr=on}} in diameter, with a mass that is 98% of the Sun.<ref>{{cite news | url = http://news.bbc.co.uk/2/hi/science/nature/4528586.stm | title = Hubble finds mass of white dwarf | first = C. | last = McGourty | work = BBC News | date=2005-12-14 | access-date=2010-01-01}}</ref>

[[File:Two Brown Dwarfs in Our Backyard.jpg|thumb|left|[[Luhman 16]], the third closest star system, contains two [[brown dwarf]]s.]]
An example of an eclipsing binary is [[Epsilon Aurigae]] in the constellation [[Auriga (constellation)|Auriga]]. The visible component belongs to the [[stellar classification|spectral class]] F0, the other (eclipsing) component is not visible. The last such eclipse occurred from 2009 to 2011, and it is hoped that the extensive observations that will likely be carried out may yield further insights into the nature of this system. Another eclipsing binary is [[Beta Lyrae]], which is a semidetached binary star system in the constellation of [[Lyra]].

Other interesting binaries include [[61 Cygni]] (a binary in the constellation [[Cygnus (constellation)|Cygnus]], composed of two [[Stellar classification|K class (orange)]] [[main sequence|main-sequence]] stars, 61 Cygni A and 61 Cygni B, which is known for its large [[proper motion]]), [[Procyon]] (the brightest star in the constellation [[Canis Minor]] and the eighth-brightest star in the night time sky, which is a binary consisting of the main star with a faint [[white dwarf]] companion), SS Lacertae (an eclipsing binary which stopped eclipsing), V907 Sco (an eclipsing binary which stopped, restarted, then stopped again), [[BG Geminorum]] (an eclipsing binary which is thought to contain a black hole with a K0 star in orbit around it), and [[2MASS J18082002−5104378]] (a binary in the "[[Milky Way#Age and cosmological history|thin disk]]" of the [[Milky Way]], and containing one of the oldest known stars).<ref name="ApJ-20181105">{{cite journal |last1=Schlaufman |first1=Kevin C. |last2=Thompson |first2=Ian B. |last3=Casey |first3=Andrew R. |title=An Ultra Metal-poor Star Near the Hydrogen-burning Limit |doi=10.3847/1538-4357/aadd97 |date=5 November 2018 |journal=[[The Astrophysical Journal]] |arxiv=1811.00549 |volume=867 |pages=98 |number=2 |bibcode=2018ApJ...867...98S |s2cid=54511945 |doi-access=free }}</ref>