Mayall II
Group of stars in the constellation Andromeda
title: "Mayall II" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["andromeda-galaxy", "globular-clusters", "andromeda-(constellation)"] description: "Group of stars in the constellation Andromeda" topic_path: "general/andromeda-galaxy" source: "https://en.wikipedia.org/wiki/Mayall_II" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Group of stars in the constellation Andromeda ::
::data[format=table title="Infobox globular cluster"]
| Field | Value |
|---|---|
| name | Mayall II |
| image | Mayall II (HST-Judy Schmidt-JPG).jpg |
| caption | Hubble Telescope image of Mayall II |
| epoch | J2000 |
| constellation | Andromeda |
| ra | {{cite simbad |
| title | NAME Mayall II |
| access-date | 2009-09-13}} |
| dec | |
| dist_ly | 2.52 ± 0.14 Mly |
| dist_pc | 770 ± 40 kpc |
| appmag_v | +13.81 |
| mass_kg | 2 |
| mass_msol | 1{{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 |
| volume | 9 |
| issue | 6 |
| pages | 641–652 |
| date | June 2009 |
| doi | 10.1088/1674-4527/9/6/003 |
| arxiv | 0904.0674 |
| radius_ly | 21.2 ± 1.0 ly (6.5 ± 0.3 pc) (Half light radius rh) and tidal radius 263.2 ± 12.7 ly (80.7 ± 3.9 pc){{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. |
| age | ~ 12 Gyr |
| names | SKHB 1, HBK 0-1 |
| :: |
| name = Mayall II | image = Mayall II (HST-Judy Schmidt-JPG).jpg | caption = Hubble Telescope image of Mayall II | epoch = J2000 | class = | constellation = Andromeda | ra = {{cite simbad | title = NAME Mayall II | access-date = 2009-09-13}} | dec = | dist_ly = 2.52 ± 0.14 Mly | dist_pc = 770 ± 40 kpc | appmag_v = +13.81 | size_v = | mass_kg = 2 | mass_msol = 1{{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}} | radius_ly = 21.2 ± 1.0 ly (6.5 ± 0.3 pc) (Half light radius rh) and tidal radius 263.2 ± 12.7 ly (80.7 ± 3.9 pc){{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}} | v_hb = | age = ~ 12 Gyr | notes = | names = SKHB 1, HBK 0-1
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 130000 ly from the Andromeda Galaxy's galactic core, and is the brightest (by absolute magnitude) globular cluster in the Local Group, with an absolute visual magnitude of −10.94 and the luminosity of 2 million Suns. 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 (~ 2 M⊙) black hole.
It was first identified as a possible globular cluster by American astronomers Nicholas Mayall and Olin J. Eggen in 1953 using a Palomar 48 in Schmidt plate exposed in 1948.
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.
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.
References
References
- (August 2001). "Mayall II=G1 in M31: Giant Globular Cluster or Core of a Dwarf Elliptical Galaxy?". The Astronomical Journal.
- admin. (2021-01-31). "Mayall II".
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