Editing Mayall II

{{Short description|Group of stars in the constellation Andromeda}}
{{Infobox globular cluster
 | name = Mayall II
 | image = Mayall II (HST-Judy Schmidt-JPG).jpg
 | caption = Hubble Telescope image of Mayall II
 | epoch = [[J2000]]
 | class = 
 | constellation = [[Andromeda (constellation)|Andromeda]]
 | ra = {{RA|00|32|46.51}}<ref name="simbad">{{cite simbad
 | title = NAME Mayall II
 | access-date = 2009-09-13}}</ref>
 | dec = {{DEC|+39|34|39.7}}<ref name="simbad"/>
 | dist_ly = 2.52 ± 0.14 [[light-year|Mly]]
 | dist_pc = 770 ± 40 [[parsec|kpc]]
 | appmag_v = +13.81<ref name="simbad"/>
 | size_v = 
 | mass_kg = 2{{e|37}}
 | mass_msol = 1{{e|7}}<ref name="Maetal2009">{{cite journal
 | bibcode = 2009RAA.....9..641M
 | title = RESEARCH PAPER: Old stellar population synthesis: new age and mass estimates for Mayall II = G1
 |author1=Ma, Jun |author2=de Grijs, Richard |author3=Fan, Zhou |author4=Rey, Soo-Chang |author5=Wu, Zhen-Yu |author6=Zhou, Xu |author7=Wu, Jiang-Hua |author8=Jiang, Zhao-Ji |author9=Chen, Jian-Sheng |author10=Lee, Kyungsook |author11=Sohn, Sangmo Tony | journal = Research in Astronomy and Astrophysics
 | volume = 9
 | issue = 6
 | pages = 641–652
 | date = June 2009
 | doi = 10.1088/1674-4527/9/6/003
 |arxiv = 0904.0674 |s2cid = 16360116}}</ref>
 | radius_ly = 21.2 ± 1.0 ly (6.5 ± 0.3 pc) (Half light radius r<sub>h</sub>) and tidal radius 263.2 ± 12.7 ly (80.7 ± 3.9 pc)<ref name="Maetal2007">{{cite journal
 | bibcode = 2007MNRAS.376.1621M
 | title = Structural parameters of Mayall II = G1 in M31
 | journal = [[Monthly Notices of the Royal Astronomical Society]]
 | volume = 376
 | issue = 4
 | pages = 1621–1629
 | date = April 2007
 | doi = 10.1111/j.1365-2966.2007.11573.x
 |author1=Ma, J. |author2=de Grijs, R. |author3=Chen, D. |author4=van den Bergh, S. |author5=Fan, Z. |author6=Wu, Z. |author7=Wu, H. |author8=Zhou, X. |author9=Wu, J. |author10=Jiang, Z. |author11=Chen, J. | doi-access=free |arxiv = astro-ph/0702012 |s2cid = 3591548}}</ref>
 | v_hb = 
 | age = ~ 12 Gyr<ref name="Maetal2009"/>
 | notes = 
 | names = SKHB 1, HBK 0-1<ref name="simbad"/>
}}

'''Mayall II''', also known as '''NGC-224-G1''', '''SKHB 1''', '''GSC 2788:2139''', '''HBK 0-1''', '''M31GC J003247+393440''' or '''Andromeda's Cluster''', is a [[globular cluster]] orbiting M31, the [[Andromeda Galaxy]].

It is located {{convert|130000|ly|kpc|lk=on}}<ref name="Maetal2007"/> from the Andromeda Galaxy's galactic core, and is the brightest<ref name="Maetal2007"/> (by [[absolute magnitude]]) globular cluster in the [[Local Group]], with an absolute visual magnitude of −10.94 and the luminosity of 2 million Suns.<ref name=":0" /> It has an [[apparent magnitude]] of 13.81 in V band. Mayall II is considered to have twice the mass of [[Omega Centauri]], and may contain a central, [[Intermediate-mass black hole|intermediate-mass]] (~ 2{{e|4}} [[solar mass|M<sub>⊙</sub>]]) [[black hole]].<ref name="Maetal2007"/>

It was first identified as a possible globular cluster by American astronomers [[Nicholas Mayall]] and [[Olin J. Eggen]] in 1953 using a [[Palomar Observatory|Palomar]] {{convert|48|in|m|adj=on}} [[Schmidt plate]] exposed in 1948.<ref name="Maetal2007"/>

Because of the widespread distribution of [[metallicity]], indicating multiple [[star]] generations and a large stellar creation period, many contend that it is not a true globular cluster, but is actually the galactic core that remains of a [[dwarf galaxy]] consumed by Andromeda.<ref name="Maetal2007"/><ref name="Meylanetal2001">{{cite journal |author1=Meylan, G. |author2=Sarajedini, A. |author3=Jablonka, P. |author4=Djorgovski, S. G. |author5=Bridges, T. |author6=Rich, R. M. | date = August 2001 | bibcode = 2001AJ....122..830M | title = Mayall II=G1 in M31: Giant Globular Cluster or Core of a Dwarf Elliptical Galaxy? | journal = The Astronomical Journal | volume = 122 | issue = 2 | pages = 830–841 | doi = 10.1086/321166 |arxiv = astro-ph/0105013 |s2cid=17778865 }}</ref>

==Origin of names==
* Mayall II is named after [[Nicholas U. Mayall]], who, with [[Olin J. Eggen]], discovered it in 1953.
* SKHB 1 is named for [[Wallace L. W. Sargent]], [[Charles T. Kowal]], [[F. D. A. Hartwick]] and [[Sidney van den Bergh]]. They also named it G1 in 1977.
* HBK 0-1 is named for [[John Huchra]], [[J. P. Brodie]] and [[S. M. Kent]] in 1991.<ref name=":0">{{Cite web |last=admin |date=2021-01-31 |title=Mayall II |url=https://www.messier-objects.com/mayall-ii/ |access-date=2024-05-10 |website=Messier Objects |language=en-US}}</ref>

==See also==
{{Portal |Astronomy}}
* [[Messier 54]]
* [[Omega Centauri]] 
* [[Mayall's Object]]

== References ==
{{reflist}}

==External links==
* [http://adsabs.harvard.edu/cgi-bin/bib_query?1991ApJ...370..495H Astrophysical Journal, Vol. 370, p. 495–504]
* [http://adsabs.harvard.edu/cgi-bin/bib_query?1953PASP...65...24M Publications of the Astronomical Society of the Pacific, Vol. 65, No. 382, p. 24–29]
* [http://adsabs.harvard.edu/cgi-bin/bib_query?1977AJ.....82..947S Astronomical Journal, vol. 82, p. 947–953]
* [http://www.nightskyinfo.com/archive/g1_globular_cluster/ NightSkyInfo.com: Mayall II]

{{Andromeda Galaxy}}{{Andromeda (constellation)}}
{{DEFAULTSORT:Mayall II}}
[[Category:Andromeda Galaxy]]
[[Category:Globular clusters]]
[[Category:Andromeda (constellation)]]