View source for NGC 2360

{{short description|Open cluster in the constellation Canis Major}}
{{Infobox open cluster|
| name = [[New General Catalogue|NGC]] 2360
| image = NGC2360 - SDSS DR14 (panorama).jpg 
| caption = [[Sloan Digital Sky Survey|SDSS]]
| credit = 
| class = Open Cluster
| epoch = [[J2000]]
| ra = {{RA|07|17|43}}<ref name="ngc-ic-project">{{cite web
 |work        = NGC/IC Project Database
 |title       = Results for NGC 2360
 |url         = http://www.ngcicproject.org/ngcicdb.asp
 |access-date  = 2010-12-03
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20120520010558/http://www.ngcicproject.org/ngcicdb.asp
 |archive-date = 2012-05-20
}}</ref>
| dec = {{DEC|-15|38|29}}<ref name="ngc-ic-project" />
| dist_ly = 
| dist_pc = 
| appmag_v = 7.2<ref name="seds" />
| size_v = 13{{prime}}<ref name="seds" />
| radius_ly = 
| absmag_v =
| constellation = [[Canis Major]]
| notes = 
| names = Caroline's Cluster,<ref name="simbad" /> [[Caldwell catalogue|Caldwell]] 58, [[Collinder catalogue|Cr]] 134, [[Melotte catalogue|Mel]] 64<ref name="simbad" />
}}
[[File:NGC 2360 map.png|thumbnail|Map showing the location of NGC 2360]]
'''NGC 2360''' (also known as '''Caroline's Cluster'''<ref name="simbad">{{cite simbad 
  | title=NGC 2360
  | access-date=2010-12-03
}}</ref> or '''Caldwell 58''') is an [[open cluster]] in the [[constellation]] [[Canis Major]]. It was discovered on 26 February 1783<ref name=hoskin05>{{cite journal|last=Hoskin|first=Michael|date=2005|title=Caroline Herschel as observer|journal=[[Journal for the History of Astronomy]]|volume=36|issue=4|pages=373–406|url=http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?2005JHA....36..373H&amp;data_type=PDF_HIGH&amp;whole_paper=YES&amp;type=PRINTER&amp;filetype=.pdf|bibcode=2005JHA....36..373H|doi=10.1177/002182860503600402|s2cid=118428465 }}</ref> by [[Caroline Herschel]], who described it as a "beautiful cluster of pretty compressed stars near 1/2 degree in diameter".<ref name="o'meara"/> Her notes were overlooked until her brother [[William Herschel|William]] included the cluster in his 1786 catalogue of 1000 clusters and nebulae and acknowledged her as the discoverer.<ref name=hoskin05/> The cluster lies 3.5 degrees east of [[Gamma Canis Majoris]] and less than one degree northwest of the [[eclipsing binary]] star [[R Canis Majoris]]; it has a combined [[apparent magnitude]] of 7.2.<ref name="o'meara">{{cite book |title=The Caldwell Objects |first=Stephen James |last=O'Meara |publisher=[[Cambridge University Press]] |date=2002 |pages=231–33|url=https://books.google.com/books?id=3Hg6YHgx9nAC&pg=PA233|isbn=978-0-521-82796-6}}</ref> It is 13 arc minutes in diameter.<ref name="seds">{{cite web
  | title=SEDS Online NGC Database
  | work=Results for NGC 2360
  | url=http://spider.seds.org/ngc/ngc.cgi?N2360
  | access-date=2010-12-03}}</ref> By the western edge of the cluster is the unrelated star, 5.5-magnitude [[HD 56405]].<ref name="streicher">{{cite web | last = Streicher  | first = Magda  | date = April 2006  | title = Caroline Herschel's Deepsky Discoveries | publisher = The Astronomical Society of Southern Africa  | work = Deepsky Delights  | url =http://www.mnassa.org.za/html/Dec2005/2005MNASSA..64..Dec..234.pdf |pages = 234–36  | access-date = 16 March 2014}}</ref>

American astronomer [[Olin J. Eggen]] surveyed the cluster in 1968, concluding that the brightest star in the field, magnitude-8.96 [[HD 56847]], is likely to lie in the field and not a true member of the cluster. He also identified one or possibly two [[blue straggler]]s.<ref>{{cite journal |title =  The Intermediate-Age Cluster NGC 2360 |author = Eggen, Olin J. | journal = The Astrophysical Journal | volume= 152 |pages= 83–87 |bibcode=1968ApJ...152...83E |url=http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1968ApJ...152...83E&amp;data_type=PDF_HIGH&amp;whole_paper=YES&amp;type=PRINTER&amp;filetype=.pdf|doi = 10.1086/149526 |year = 1968 }}</ref> These are unexpectedly hot and luminous stars that appear younger than surrounding stars, and have likely developed by sucking matter off companion stars.<ref>{{cite web|url=http://www.northwestern.edu/newscenter/stories/2011/10/blue-stragglers.html|title=Astronomers Explain 'Blue Stragglers'|last=Fellman|first=Megan|date=17 October 2011|work=News|publisher=[[Northwestern University]]|access-date=18 March 2014|location=Evanston, Illinois}}</ref> Four are now recognised to be in the cluster.<ref>{{cite journal|author=Ahumada, J. A. |author2=Lapasset, E.|date=2007|title=New catalogue of blue stragglers in open clusters|journal= [[Astronomy and Astrophysics]]|volume=463|issue=2|pages=789–97|bibcode=2007A&A...463..789A|doi = 10.1051/0004-6361:20054590 |url=https://zenodo.org/record/895410|doi-access=free}}</ref> By analysing the masses of the smallest stars that have evolved into [[red giant]]s—namely, stars of 1.8 or 1.9 solar masses—Swiss astronomers Jean-Claude Mermilliod and [[Michel Mayor]] were able to date the age of the cluster at 2.2 billion years.<ref name="Mermilliod">{{cite journal|author=Mermilliod, Jean-Claude |author2=Mayor, Michel |date=1990|title= Red Giants in Open Clusters. III – Binarity and Stellar Evolution in Five Intermediate-age Clusters: NGC 2360, 2423, 5822, 6811, and IC 4756|journal=Astronomy and Astrophysics |volume=273|issue=1|pages= 61–72|url=http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1990A%26A...237...61M&amp;data_type=PDF_HIGH&amp;whole_paper=YES&amp;type=PRINTER&amp;filetype=.pdf |bibcode=1990A&A...237...61M}}</ref>  The cluster has a diameter of around 15 light-years and is located 3700 light-years from Earth.<ref name="o'meara"/>

{| class=wikitable width=250
|[[File:Sirius Mirzam M41.jpg|250px]]<BR>[[Sirius]] and [[Messier 41|M41]] (lower right), [[Messier 50|M50]] (upper left), and NGC 2360 (lower left)
|}

==Notes==
{{reflist}}

==External links==
{{commonscat}}
* {{WikiSky}}


{{Sky|07|17|42|-|15|38|00|6150}}
{{Catalogs|NGC=2360|C=58|Collinder=123}}
{{Ngc25}}
{{Caldwell catalogue}}
{{Canis Major}}

{{DEFAULTSORT:NGC 2360}}
[[Category:Canis Major]]
[[Category:NGC objects|2360]]
[[Category:Open clusters]]
[[Category:Caldwell objects|058b]]
[[Category:Astronomical objects discovered in 1783]]