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Information About

Gamma Andromedae




name=Gamma Andromedae 1/2Aab/2B }}
  Epoch J2000
  Ra 02<sup>h</sup> 03<sup>m</sup> 540<sup>s</sup>
  Dec +42&deg 19&prime 47&Prime
  Appmag V 210/51/63


  Class K3 IIb/B8 V/A0 V
  B-v 137/003
  U-b 158/-012


  Radial V -12
  Prop Mo Ra 4308
  Prop Mo Dec -5085
  Parallax 919
  P Error 073
  Dist Ly 355
  Dist Pc 109


  Mass
  Radius 80
  Luminosity 2,000
  Temperature 4,500/10,000/10,000
  Metal
  Rotation <14/70 km/sec





Gamma Andromedae (γ And / γ Andromedae) is a four Star System in the Constellation Andromeda . It is also known by the traditional name '''Almach''' (also written as '''Almaach''', '''Almak''', '''Alamak''').

In small telescopes, Almach can be easily resolved as a double star, and is a very interesting and beautiful sight for amateur astronomers. The main star (γ¹) is a K3- Supergiant of spectral type K3 and a Brightness of +2.13 M . The companion (γ²) with a brightness of +4.84 m is 9.6" away at a Position Angle of 63 degrees.

Interestingly, γ² itself can be resolved as a double star with much larger telescopes. Its two components are a B8 Main Sequence Dwarf with Apparent Magnitude of +5.1, and an A0 dwarf with an apparent magnitude of +6.3. They have an orbital period of 61 years. The brighter of these is known to be a Spectroscopic Binary itself, with an orbital period of 2.67 days. Thus γ² is a triple star.

In the '' Foundation '' novels by Isaac Asimov , the star Gamma Andromedae is a populated star system, Gamma Andromeda .