Gamma Cephei

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γ Cephei (Gamma Cephei; proper name Errai or Alrai from Arabic الراعي, DMG ar - ʿ ī rā, the shepherd / shepherd '), is a star of spectral type K1 IV with an apparent brightness of 3.2 mag. The distance from the Earth is about 45 light-years.

γ Cephei is a double star, consisting of a sub- giant and a red dwarf. The red dwarf moves on a track with a semi-major axis of 20 AU and an eccentricity of 0.41 to the subgiant. One orbit takes it around 70 years.

γ Cephei will be the next visible with the naked eye star in the north celestial pole due to the precession of the Earth's axis. By shifting the Earth's axis, the star is moving toward the north celestial pole and apparently is from the year 3000 a smaller distance to the north celestial pole than Polaris. Its closest approach will take place around the year 4000, before he ι Cephei will follow in the role of Polaris around the year 5200.

In 1989, the discovery of an exoplanet around γ Cephei by Anthony Lawton and P. Wright was announced. That would have been the first discovery of such a planet, based on the measurement of the radial velocity of the system, which successfully planets have been detected around other stars later. The discovery, however, was revoked in 1992. Later, in 2002, new measurements corroborated the existence of the planet γ Cephei Ab, which therefore in about 900 days orbiting the star once and having at least 1.6 times the mass of Jupiter.

It is speculated that the system may prevail conditions that allow the development of life. The Franco-German TV channel Arte Culture submitted by 30 September 2006 via parabolic antenna of the Space Centre CNES simultaneously emitted in Europe telecast Cosmic Connexion in the direction of γ Cephei, hoping to achieve a pos living there civilization. In the 160 - minute show, the hoped-for aliens the man and his life is shown. The broadcast will reach γ Cephei in 2051. A possible response of the aliens would arrive no earlier than 2096 on Earth. Because of the large distance are broadcast and reply every 45 years on the road.