Mayall II
Encyclopedia
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
Globular cluster
A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is...

 orbiting M31, the Andromeda Galaxy
Andromeda Galaxy
The Andromeda Galaxy is a spiral galaxy approximately 2.5 million light-years from Earth in the constellation Andromeda. It is also known as Messier 31, M31, or NGC 224, and is often referred to as the Great Andromeda Nebula in older texts. Andromeda is the nearest spiral galaxy to the...

.

It is located 130,000 light-year
Light-year
A light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...

s (40 kpc) from Andromeda's galactic core, and is the brightest (absolute magnitude
Absolute magnitude
Absolute magnitude is the measure of a celestial object's intrinsic brightness. it is also the apparent magnitude a star would have if it were 32.6 light years away from Earth...

) globular cluster in the Local Group
Local Group
The Local Group is the group of galaxies that includes Earth's galaxy, the Milky Way. The group comprises more than 30 galaxies , with its gravitational center located somewhere between the Milky Way and the Andromeda Galaxy...

, having an apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...

 of 13.7. G1 is considered to have twice the mass of Omega Centauri
Omega Centauri
Omega Centauri or NGC 5139 is a globular clusterin the constellation of Centaurus, discovered by Edmond Halley in 1677 who listed it as a nebula. Omega Centauri had been listed in Ptolemy's catalog 2000 years ago as a star. Lacaille included it in his catalog as number I.5...

. G1 may contain a central, intermediate-mass (∼ 2 M
Solar mass
The solar mass , , is a standard unit of mass in astronomy, used to indicate the masses of other stars and galaxies...

) black hole.

It was first identified as a possible globular cluster by Nicholas Mayall & O.J. Eggen in 1953 using a Palomar
Palomar Observatory
Palomar Observatory is a privately owned observatory located in San Diego County, California, southeast of Pasadena's Mount Wilson Observatory, in the Palomar Mountain Range. At approximately elevation, it is owned and operated by the California Institute of Technology...

 48-inch Schmidt plate exposed in 1948.

Because of the widespread distribution of metallicity
Metallicity
In astronomy and physical cosmology, the metallicity of an object is the proportion of its matter made up of chemical elements other than hydrogen and helium...

, indicating multiple star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

 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
Dwarf galaxy
A dwarf galaxy is a small galaxy composed of up to several billion stars, a small number compared to our own Milky Way's 200-400 billion stars...

 consumed by Andromeda.

Origin of names

Mayall II is named after Nicholas U. Mayall, who, with O.J. Eggen, discovered it in 1953.

SKHB 1 is named for Wallace L. W. Sargent
Wallace L. W. Sargent
Wallace Leslie William Sargent is an American astronomer. He is often known as Wal Sargent. Although now a U.S. citizen, he was born in Elsham, England. He received his Ph.D...

, C.T. Kowal, F.D.A. Hartwick, and Sidney van den Bergh
Sidney van den Bergh
Sidney Van den Bergh, OC, FRS is a retired Canadian astronomer.Born in the Netherlands, son of businessman and politician Sidney James van den Bergh and grandson of Unilever co-founder Samuel van den Bergh, he showed an interest in science from an early age, learning to read with books on astronomy...

. They also named it G1 in 1977.

HBK 0-1 is named for J.P. Huchra, J.P. Brodie, and S.M. Kent in 1991.

See also

  • Messier 54
    Messier 54
    Messier 54 is a globular cluster in the constellation Sagittarius. It was discovered by Charles Messier in 1778 and subsequently included in his catalog of comet-like objects....

  • Omega Centauri
    Omega Centauri
    Omega Centauri or NGC 5139 is a globular clusterin the constellation of Centaurus, discovered by Edmond Halley in 1677 who listed it as a nebula. Omega Centauri had been listed in Ptolemy's catalog 2000 years ago as a star. Lacaille included it in his catalog as number I.5...


  • Mayall III (M31 G2, G2
    G2
    G2, G02, G.II, G II, or G-2 may refer to:-Media:* G2, The Guardian weekday supplement* Gladiators 2000, 1994 spinoff of American Gladiators-Fiction:...

    , HBK 0-2, SKHB 2, M31GC J003334+393119)
  • Mayall IV (HBK 358-219, SKHB 219, Bol 358, M31GC J004318+394914)
  • Mayall V (HBK 407-352, SKHB 352, Bol 407, M31GC J005010+414101)
  • Mayall VI (HBK 0-327, SKHB 327, BA 3-29, M31GC J004650+424445)

  • Mayall's Object
    Mayall's Object
    Mayall's Object is the result of two colliding galaxies located 500 million light years away within the constellation of Ursa Major. It was discovered by Nicholas U. Mayall of the Lick Observatory on 13 March 1940, using the Crossley reflector...

     (Arp 148 or APG 148, VV32)

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK