Hubble Telescope image of Mayall II, colour picture assembled from separate images taken in visible and near-infrared wavelengths in July 1994.
Credit: Michael Rich, Kenneth Mighell, and James D. Neill (Columbia University), and Wendy Freedman (Carnegie Observatories) and NASA
|Observation data (J2000 epoch)|
|Right ascension||00h 32m 46.51s|
|Declination||+39° 34′ 39.7″|
|Distance||2.52 ± 0.14 Mly (770 ± 40 kpc)|
|Apparent magnitude (V)||+13.8|
|Mass||1×107 M☉ (2×1037 kg)|
|Radius||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) |
|Estimated age||~ 12 Gyr |
|Other designations||SKHB 1, HBK 0-1|
It is located 130,000 light-years (40 kpc) from the Andromeda Galaxy's galactic core, and is the brightest (by absolute magnitude) globular cluster in the Local Group, having an apparent magnitude of 13.7. Mayall II is considered to have twice the mass of Omega Centauri, and may contain a central, intermediate-mass (∼ 2×104 M⊙) black hole.
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 namesEdit
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- 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.
- "SIMBAD Astronomical Database". Results for Mayall II. Retrieved 2009-09-13.
- Ma, Jun; de Grijs, Richard; Fan, Zhou; Rey, Soo-Chang; Wu, Zhen-Yu; Zhou, Xu; Wu, Jiang-Hua; Jiang, Zhao-Ji; Chen, Jian-Sheng; Lee, Kyungsook; Sohn, Sangmo Tony (June 2009). "RESEARCH PAPER: Old stellar population synthesis: new age and mass estimates for Mayall II = G1". Research in Astronomy and Astrophysics. 9 (6): 641–652. Bibcode:2009RAA.....9..641M. arXiv: . doi:10.1088/1674-4527/9/6/003.
- Ma, J.; de Grijs, R.; Chen, D.; van den Bergh, S.; Fan, Z.; Wu, Z.; Wu, H.; Zhou, X.; Wu, J.; Jiang, Z.; Chen, J. (April 2007). "Structural parameters of Mayall II = G1 in M31". Monthly Notices of the Royal Astronomical Society. 376 (4): 1621–1629. Bibcode:2007MNRAS.376.1621M. arXiv: . doi:10.1111/j.1365-2966.2007.11573.x.
- Meylan, G.; Sarajedini, A.; Jablonka, P.; Djorgovski, S. G.; Bridges, T.; Rich, R. M. (August 2001). "Mayall II=G1 in M31: Giant Globular Cluster or Core of a Dwarf Elliptical Galaxy?". The Astronomical Journal. 122 (2): 830–841. Bibcode:2001AJ....122..830M. arXiv: . doi:10.1086/321166.