View source for NGC 206

{{Short description|OB association in the Andromeda Galaxy}}
{{Use dmy dates|date=December 2023}}
{{Infobox cluster
| image = [[File:NGC206.jpg|300px]]
| caption = NGC 206
| name = [[New General Catalogue|NGC]] 206
| epoch = [[J2000]]
| ra = {{RA|00|40|31.3}}<ref name="ned">{{cite web
  | title=NASA/IPAC Extragalactic Database
  | work=Results for NGC 206
  | url=http://nedwww.ipac.caltech.edu/
  | access-date=25 November 2006 }}</ref>
| dec = {{DEC|+40|44|21}}<ref name="ned" />
| dist_ly =
| dist_pc =
| appmag_v =
| size_v = 4.2′ ([[Minute of arc|arcmin]])
| radius_ly = Ca. 400 ly
| absmag_v = Unknown
| constellation = [[Andromeda (constellation)|Andromeda]]
| notes =
| names =
}}

'''NGC 206''' is a bright [[star cloud]] in the [[Andromeda Galaxy]], and the brightest star cloud in Andromeda when viewed from [[Earth]]. It was discovered by German-born English astronomer William Herschel in 1786<ref>{{Cite web |title=New General Catalog Objects: NGC 200 - 249 |url=https://cseligman.com/text/atlas/ngc2.htm#206 |access-date=2025-02-17 |website=cseligman.com}}</ref> and possibly even two years earlier when he observed "a streak of milky nebulosity, horizontal, or part of the 31st Nebula."

==Features==
NGC 206 is the richest and most conspicuous star cloud in the Andromeda Galaxy, and is one of the largest and brightest star-forming regions in the [[Local Group]].<ref name=Massey1995>
{{cite journal
| volume = 110
| pages = 2715
| last1 = Massey
| first1 = Philip
| last2 = Armandroff
| first2 = Taft E.
| last3 = Pyke
| first3 = Randall
| last4 = Patel
| first4 = Kanan
| last5 = Wilson
| first5 = Christine D.
| title = Hot, Luminous Stars in Selected Regions of NGC 6822, M31, and M33.
| journal = Astronomical Journal
| year = 1995
|bibcode = 1995AJ....110.2715M
| doi = 10.1086/117725
}}</ref> It contains more than 300 stars brighter than M<sub>b</sub>=−3.6.<ref>{{Cite book|title=The Andromeda Galaxy|first=Paul W.|last=Hodge|author-link=Paul W. Hodge|year=1992|publisher=[[Springer Science+Business Media|Springer]]|page=153}}</ref> It was originally identified by [[Edwin Hubble]] as a star cluster but today, due to its size, it is classified as an [[OB association]].<ref>{{Cite book |url= https://books.google.com/books?id=71FRczXVBWgC&pg=PA20|title=The Andromeda Galaxy  |first=Paul W.  |last=Hodge|page=20 |publisher=Springer Science & Business Media|year= 1992|isbn=978-0-7923-1654-1}}</ref>

NGC 206 is located in a [[spiral arm]] of the Andromeda Galaxy, in a zone free of [[neutral hydrogen]]. It contains hundreds of stars of [[Stellar classification|spectral types]] [[O-type main-sequence star|O]] and [[B-type main-sequence star|B]]. The star cloud has a double structure: one region has an age of around 10 million years and includes several [[H II region]]s in its border; the other region has an age of 40 to 50 million years and includes a number of [[Cepheid variable|cepheids]]. The two regions are separated by a band of [[cosmic dust|interstellar dust]].<ref name=Chernin1995>
{{cite journal
| volume = 275
| issue = 2
| pages = 313–326
| last1 = Chernin
| first1 = Arthur D.
| last2 = Efremov
| first2 = Yury N.
| last3 = Voinovich
| first3 = Peter A.
| title = Superassociations: violent star formation induced by shock-shock collisions.
| journal = [[Monthly Notices of the Royal Astronomical Society]]
| year = 1995
| bibcode = 1995MNRAS.275..313C
| doi = 10.1093/mnras/275.2.313
| doi-access = free
}}</ref>

==See also==
{{Portal |Astronomy}}
* [[List of Andromeda's satellite galaxies]]

== References ==
{{Reflist}}

== External links ==
{{commonscat}}
* [http://messier.seds.org/more/m031_n206.html NGC 206 @ SEDS NGC objects pages]
* {{WikiSky}}
* {{APOD |date=2 April 1999|title=Stars of NGC 206}}

{{Sky|00|40|31.3|+|40|44|21|2500000}}
{{Andromeda Galaxy}}
{{Ngc5}}{{Andromeda (constellation)}}
{{DEFAULTSORT:NGC 0206}}
[[Category:Star clouds]]
[[Category:Andromeda Galaxy]]
[[Category:Andromeda (constellation)]]
[[Category:NGC objects|0206]]