Mayall II
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 130,000 light-years from the Andromeda Galaxy's galactic core, and is the brightest globular cluster in the Local Group, having 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.
It was first identified as a possible globular cluster by American astronomers Nicholas Mayall and Olin J. Eggen in 1953 using a Palomar 48-inch 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.- 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.
