Editing Messier 3

{{Short description|Globular cluster in the constellation Canes Venatici}}
{{Infobox globular cluster
| name = Messier 3  
| image = [[File:Messier 3 - Adam Block - Mount Lemmon SkyCenter - University of Arizona.jpg|300px]]
| caption = Globular cluster Messier 3 in Canes Venatici
| credit = 
| epoch = [[J2000]]
| class = VI<ref name=thompson_thompson2007/><ref name=hcob849_11 />
| constellation = [[Canes Venatici]]
| ra = {{RA|13|42|11.62}}<ref name=aj140_6_1830/>
| dec = {{DEC|+28|22|38.2}}<ref name=aj140_6_1830/>
| dist_ly = {{Convert|33.9|kly|kpc|abbr=on|lk=on}}<ref name=aj139_2_476/>
| appmag_v = 6.39<ref name="aj144_5_126"/>
| size_v = 18′.0
| mass_msol = {{Val|4.5|e=5}}<ref name=mnras406_3_2000/>
| radius_ly = {{Convert|103.0|pc|ly|abbr=on|lk=on|sigfig=4}}<ref name="Brosche"/>
| radius_tidal_ly = {{Convert|113|pc|ly|abbr=on|lk=on|sigfig=2}}<sup>[mean]</sup><ref name="Brosche"/>
| metal_fe = –1.34<ref name=mnras404_3_1203/>
| age = 11.39&nbsp;[[Gigayear|Gyr]]<ref name=mnras404_3_1203/>
| absmag_v = -8.93
| names = [[New General Catalogue|NGC]] 5272<ref name="simbad">{{cite simbad | title=M 3 | access-date=2006-11-15 | postscript=. }}</ref>
}}

'''Messier 3''' ('''M3'''; also '''NGC 5272''') is a [[globular cluster]] of stars in the northern [[constellation]] of [[Canes Venatici]]. 

== Discovery ==
It was discovered on May 3, 1764,<ref name="machholz2002" /> and was the first Messier object to be discovered by [[Charles Messier]] himself. Messier originally mistook the object for a nebula without stars. This mistake was corrected after the stars were resolved by [[William Herschel]] around 1784.<ref name=":0">{{Cite news|url=https://www.nasa.gov/feature/goddard/2017/messier-3|title=Messier 3|last=Garner|first=Rob|date=2017-10-06|work=NASA|access-date=2018-04-13|language=en}}</ref> Since then, it has become one of the best-studied globular clusters. Identification of the cluster's unusually large [[variable star]] population was begun in 1913 by American astronomer [[Solon Irving Bailey]] and new variable members continue to be identified up through 2004.<ref name="aaa487_1_185" />

== Visibility ==
[[File:Messier 3 - Globular cluster.png|thumb|left|Messier 3 by amateur astrophotographer Anthony MICHEL<ref>{{cite web|title=Messier 3 - Globular cluster |url=https://app.astrobin.com/i/i4a8w4}}<!-- auto-translated from French by Module:CS1 translator --></ref>]]

Many amateur astronomers consider it one of the finest northern globular clusters, following only [[Messier 13]].<ref name=thompson_thompson2007/> M3 has an [[apparent magnitude]] of 6.2,<ref name="simbad"/> making it a difficult [[naked eye]] target<ref name=OMeara1998 /> even with [[Bortle Dark-Sky Scale|dark conditions]] with [[averted vision]]. However, with a moderate-sized telescope, the cluster can be seen as a cloudy smudge even in severely light-polluted skies, and can be further defined in darker conditions. It can be found by looking almost exactly halfway along the north-west line that would join [[Arcturus]] (α Boötis) to [[Cor Caroli]] (α Canum Venaticorum). Using a telescope with a {{Convert|25|cm|in|abbr=on}} [[aperture]], the cluster has a bright core with a diameter of about 6&nbsp;[[arcminute]]s and spans a total of double that.<ref name=thompson_thompson2007/>

== Characteristics ==
This cluster is one of the largest and brightest, and is made up of around 500,000 stars.<ref name=":0" /> It is estimated to be 11.4 billion years old.<ref name=mnras404_3_1203/> It is centered at 32,600 [[light-year]]s (10.0 [[Parsec|kpc]]) away from [[Earth]].<ref>{{Cite journal|last1=Cacciari|first1=C.|last2=Corwin|first2=T. M.|last3=Carney|first3=B. W.|date=January 2005|title=A Multicolor and Fourier Study of RR Lyrae Variables in the Globular Cluster NGC 5272 (M3)|url=https://iopscience.iop.org/article/10.1086/426325|journal=The Astronomical Journal|language=en|volume=129|issue=1|pages=267–302|doi=10.1086/426325|s2cid=8875833 |issn=0004-6256|arxiv=astro-ph/0409567}}</ref>

Messier 3 is quite isolated as it is {{Convert|31.6|kly|kpc|abbr=on|lk=on}} above the [[Galactic plane]] and roughly {{Convert|38.8|kly|kpc|abbr=on|lk=off}} from the center of the [[Milky Way]]. It contains 274 known [[variable star]]s, by far the most found in any globular cluster. These include 133 [[RR Lyrae variables]], of which about a third display the [[Blazhko effect]] of long-period modulation. The overall abundance of elements other than hydrogen and helium, what astronomers term the [[metallicity]], is in the range of &minus;1.34 to &minus;1.50 [[Decimal exponent|dex]]. This value gives the [[logarithm]] of the abundance relative to the [[Sun]]; the actual proportion is 3.2&ndash;4.6% of the solar abundance. Messier 3 is the prototype for the [[Oosterhoff type I]] cluster, which is considered "metal-rich". That is, for a globular cluster, Messier 3 has a relatively high abundance of heavier elements.<ref name=aj129_1_267/>

[[File:M3map.png|thumb|[[Arcturus]] and [[Cor Caroli]] can be used to help locate M3]]

==References==
{{Reflist|35em|refs=
<ref name=aj140_6_1830>{{citation | display-authors=1 | last1=Goldsbury | first1=Ryan | last2=Richer | first2=Harvey B. | last3=Anderson | first3=Jay | last4=Dotter | first4=Aaron | last5=Sarajedini | first5=Ata | last6=Woodley | first6=Kristin | title=The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters | journal=The Astronomical Journal | volume=140 | issue=6 | pages=1830–1837 |date=December 2010 | doi=10.1088/0004-6256/140/6/1830 | bibcode=2010AJ....140.1830G | postscript=. |arxiv = 1008.2755 | s2cid=119183070 }}</ref>

<ref name=aj129_1_267>{{citation | last1=Cacciari | first1=C. | last2=Corwin | first2=T. M. | last3=Carney | first3=B. W. | title=A Multicolor and Fourier Study of RR Lyrae Variables in the Globular Cluster NGC 5272 (M3) | journal=The Astronomical Journal | volume=129 | issue=1 | pages=267–302 |date=January 2005 | doi=10.1086/426325 | bibcode=2005AJ....129..267C |arxiv = astro-ph/0409567 | s2cid=8875833 | postscript=. }}</ref>

<ref name=aaa487_1_185>{{citation | last1=Valcarce | first1=A. A. R. | last2=Catelan | first2=M. | title=A semi-empirical study of the mass distribution of horizontal branch stars in M 3 (NGC 5272) | journal=Astronomy and Astrophysics | volume=487 | issue=1 | pages=185–195 |date=August 2008 | doi=10.1051/0004-6361:20078231 | bibcode=2008A&A...487..185V | postscript=. |arxiv = 0805.3161 | s2cid=11097003 }}</ref>

<ref name=thompson_thompson2007>{{citation | first1=Robert Bruce | last1=Thompson | first2=Barbara Fritchman | last2=Thompson | title=Illustrated guide to astronomical wonders | series=DIY science O'Reilly Series | publisher=[[O'Reilly Media, Inc.]] | date=2007 | isbn=978-0-596-52685-6 | page=137 | url=https://books.google.com/books?id=ymt9nj_uPhwC&pg=PA137 | postscript=. }}</ref>

<ref name="aj144_5_126">{{citation | last1=Delessandro | first1=Emanuele | last2=Schiavon | first2=Ricardo P. | last3=Rood | first3=Robert P. | last4=Ferraro | first4=Francesco R. | last5=Sohn| first5=Sangmo T.  | last6=Lanzoni | first6=Barbara | last7=O'Connell | first7=Robert W. | title=Ultraviolet Properties of Galactic Globular Clusters with Galex. II. Integrated Colors  | journal=[[The Astronomical Journal]] | volume=144 | issue=5 | pages=126–139 |date=September 2012 | doi=10.1088/0004-6256/144/5/126 | bibcode=2012AJ....144..126D | postscript=. |arxiv = 1208.5698 | s2cid=56419886 }} </ref>

<ref name=machholz2002>{{citation | first1=Don | last1=Machholz | title=The observing guide to the Messier marathon: a handbook and atlas | publisher=[[Cambridge University Press]] | date=2002 | isbn=978-0-521-80386-1 | url=https://books.google.com/books?id=iGI1wjkGLkQC&pg=PA12 | postscript=. }}</ref>

<ref name=mnras404_3_1203>{{citation | last1=Forbes | first1=Duncan A. | last2=Bridges | first2=Terry | title=Accreted versus in situ Milky Way globular clusters | journal=[[Monthly Notices of the Royal Astronomical Society]] | volume=404 | issue=3 | pages=1203–1214 |date=May 2010 | doi=10.1111/j.1365-2966.2010.16373.x | doi-access=free | bibcode=2010MNRAS.404.1203F | postscript=. |arxiv = 1001.4289 | s2cid=51825384 }}</ref>

<ref name=mnras406_3_2000>{{citation | last1=Marks | first1=Michael | last2=Kroupa | first2=Pavel | title=Initial conditions for globular clusters and assembly of the old globular cluster population of the Milky Way | journal=Monthly Notices of the Royal Astronomical Society | volume=406 | issue=3 | pages=2000–2012 |date=August 2010 | doi=10.1111/j.1365-2966.2010.16813.x | doi-access=free | bibcode=2010MNRAS.406.2000M | postscript=. |arxiv = 1004.2255 | s2cid=118652005 }} Mass is from M<sub>PD</sub> on Table 1.</ref>

<ref name=aj139_2_476>{{citation | display-authors=1 | last1=Paust | first1=Nathaniel E. Q. | last2=Reid | first2=I. Neill | last3=Piotto | first3=Giampaolo | last4=Aparicio | first4=Antonio | last5=Anderson | first5=Jay | last6=Sarajedini | first6=Ata | last7=Bedin | first7=Luigi R. | last8=Chaboyer | first8=Brian | last9=Dotter | first9=Aaron | title=The ACS Survey of Galactic Globular Clusters. VIII. Effects of Environment on Globular Cluster Global Mass Functions | journal=The Astronomical Journal | volume= 139 | issue= 2 | pages= 476–491 |date=February 2010 | doi=10.1088/0004-6256/139/2/476 | bibcode=2010AJ....139..476P | postscript=. | hdl=2152/34371 | s2cid=120965440 | hdl-access=free }}</ref>

<ref name=hcob849_11>{{citation | last1=Shapley | first1=Harlow | last2=Sawyer | first2=Helen B. | title=A Classification of Globular Clusters | journal=Harvard College Observatory Bulletin | issue=849 | pages=11–14 |date=August 1927 | bibcode=1927BHarO.849...11S | postscript=. | volume=849 }}</ref>

<ref name=OMeara1998>{{citation
 | title=Deep-Sky Companions: The Messier Objects
 | first1=Stephen James | last1=O'Meara | first2=David H. | last2=Levy 
 | publisher=Cambridge University Press | postscript=.
 | year=1998 | isbn=978-0521553322 | page=45
 | url=https://books.google.com/books?id=jis4evHuuzUC&pg=PA45 }}</ref>

<ref name="Brosche">
{{cite journal
 | last1       = Brosche | first1 = P.
 | last2      = Odenkirchen | first2 = M.
 | last3      = Geffert | first3  = M.
 | date       = March 1999
 | title      = Instantaneous and average tidal radii of globular clusters
 | journal    = New Astronomy
 | volume     = 4
 | issue      = 2
 | pages      = 133–139
 | bibcode    = 1999NewA....4..133B
 | doi        = 10.1016/S1384-1076(99)00014-7
}}</ref>

}}

==See also==
* [[Messier object#Messier_objects|List of Messier objects]]

==External links==
{{commonscat}}
* [http://www.messier.seds.org/m/m003.html SEDS Messier pages on M3]
* [http://gclusters.altervista.org/cluster_4.php?ggc=M+3 M3, Galactic Globular Clusters Database page]
* [http://www.darkatmospheres.com/astro/gallery/clusters/enlarge.php?fileBase=clusters_4 M3 Photo detail Dark Atmospheres]
* {{cite web|last=Merrifield|first=Michael|title=M3 – Globular Cluster|url=http://www.deepskyvideos.com/videos/messier/M3_globular_cluster.html|work=Deep Sky Videos|publisher=[[Brady Haran]]}}
* {{WikiSky}}


{{Sky|13|42|11.23||28|22|31.6|33900}}
{{Portal bar|Astronomy|Stars|Outer space}}
{{Messier objects}}
{{Ngc55}}
{{Canes Venatici}}

{{DEFAULTSORT:Messier 3}}
[[Category:Globular clusters|Messier 003]]
[[Category:Canes Venatici|Messier 003]]
[[Category:Messier objects|003]]
[[Category:NGC objects|Messier 003]]
[[Category:Astronomical objects discovered in 1764|17640503]]
[[Category:Discoveries by Charles Messier]]