Messier 69
{{short description|Globular cluster in the constellation Sagittarius}}
{{Use mdy dates|date=April 2012}}
{{Infobox globular cluster
| name = Messier 69
| image = 300px
| caption = Globular cluster Messier 69 by Hubble Space Telescope; 3.5{{prime}} view
| epoch = J2000
| constellation = Sagittarius
| dist_ly = {{Convert|8.8|kpc|kly|order=flip|abbr=on}}
| appmag_v = 7.6{{cite web |url=https://messier.seds.org/m/m069.html |title=Messier 69 |access-date=30 April 2022 |website=SEDS Messier Catalog}}
| mass_msol = {{Val|2.0|e=5|ul=solar mass}}
| radius_ly = 45 lyFrom trigonometry: distance × sin( diameter_angle / 2 ) = 28,700 × 0.00157 = 45 ly. radius
| radius_tidal_ly = {{Convert|28.17|pc|ly|abbr=on|disp=out}}.
| v_hb =
| age = 13.06 Gyr
| notes =
| names = GCl 96, M69, NGC 6637,NGC 6634
}}
Messier 69 or M69, also known NGC 6637, and NGC 6634,{{Cite web |title=Your NED Search Results |url=https://ned.ipac.caltech.edu/cgi-bin/objsearch?objname=NGC+6634&extend=no&hconst=73&omegam=0.27&omegav=0.73&corr_z=1&out_csys=Equatorial&out_equinox=J2000.0&obj_sort=RA+or+Longitude&of=pre_text&zv_breaker=30000.0&list_limit=5&img_stamp=YES |access-date=2024-08-31 |website=ned.ipac.caltech.edu}}{{Cite web |title=NGC/IC Project Restoration Efforts |url=https://ngcicproject.observers.org/NGC/NGC_66xx/NGC_6634.htm |access-date=2024-08-31 |website=ngcicproject.observers.org}} is a globular cluster in the southern constellation of Sagittarius.{{efn|In daily rising of this globular cluster, whether in day- or nighttime, it will reach 15° above the due southern horizon, at the 90°−32°−15° parallel thus the 43rd parallel north, the furthest north for very detailed, easy observation for this object}} It can be found 2.5° to the northeast of the star Epsilon Sagittarii and is dimly visible in 50 mm aperture binoculars. The cluster was discovered by Charles Messier on August 31, 1780, the same night he discovered M70. At the time, he was searching for an object described by Nicolas-Louis de Lacaille in 1751–2 and thought he had rediscovered it, but it is unclear if Lacaille actually described M69.
This cluster is about 28,700 light-years away from Earth and {{Convert|1.6|kpc|ly|disp=out}} from the Galactic Center, with a spatial radius of 45 light-years. It is a relatively metal-rich globular cluster that is a likely member of the galactic bulge population. It has a mass of {{Val|200,000|ul=solar mass}} with a half-mass radius of {{Convert|3.56|pc|ly|abbr=on|disp=out}}, a core radius of {{Convert|8.94|pc|ly|abbr=on|disp=out}}, and a tidal radius of {{Convert|28.17|pc|ly|abbr=on|disp=out}}. Its center has a bright luminosity density of {{Val|6,460|ul=solar luminosity|fmt=commas}}·pc−3 (meaning per cubic parsec). It is a close neighbor of its analog M70 – possibly only 1,800 light-years separates the two.
Gallery
File:Messier 69 Hubble WikiSky.jpg|As globular clusters go, M69 is one of the most metal-rich on record.{{cite news|title=Cosmic riches|url=http://www.spacetelescope.org/images/potw1240a/|access-date=3 October 2012|newspaper=ESA/Hubble Picture of the Week}}
File:M69map.png|Map showing location of M69
See also
References and footnotes
{{reflist|refs=
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| title=Globular Cluster M69 | date=July 20, 2011 | work=SEDS Messier pages
| publisher=Students for the Exploration and Development of Space (SEDS)
| url=http://messier.seds.org/m/m069.html
| access-date=2018-12-03 | postscript=. }}
| title=Hubble Space Telescope Photometry of the Metal-rich Globular Clusters NGC 6624 and NGC 6637
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| title=HST color-magnitude diagrams of 74 galactic globular clusters in the HST F439W and F555W bands
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| title=Illustrated Guide to Astronomical Wonders: From Novice to Master Observer
| first1=Robert Bruce | last1=Thompson | first2=Barbara Fritchman | last2=Thompson
| publisher=Maker Media, Inc. | year=2007 | isbn=978-1680451917
| url=https://books.google.com/books?id=y24CCwAAQBAJ&pg=PT872 }}
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| title=The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters
| journal=The Astronomical Journal | display-authors=1
| volume=140 | issue=6 | pages=1830–1837 | date=December 2010
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| journal=Harvard College Observatory Bulletin
| volume=849 | issue=849 | pages=11–14 |date=August 1927
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| last1=Forbes | first1=Duncan A. | last2=Bridges | first2=Terry
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| bibcode=2010MNRAS.404.1203F | arxiv=1001.4289 | s2cid=51825384 }}
{{cite simbad | title=NGC 6637 | access-date=2006-11-17 }}
}}
{{notelist}}
External links
{{commons category}}
- [http://gclusters.altervista.org/cluster_4.php?ggc=M+69 Messier 69, Galactic Globular Clusters Database page]
- {{WikiSky}}
{{Sky|18|31|23.23|-|32|20|52.7|29700}}
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{{Messier objects}}
{{Ngc70}}
Category:Sagittarius (constellation)