Gamma Cephei (γ Cep / γ Cephei) is a star in the constellation Cepheus. It also has the traditional name Alrai, also known as Errai (or Er Rai). In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. ... The J2000. ... Orion is a remarkable constellation, visible from most places on the globe at one time or another during the year. ... Cepheus is a northern constellation named after King Cepheus in Greek mythology, and is considered to represent a king. ... Right ascension (RA; symbol α: Greek letter alpha) is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. ... In astronomy, declination (dec) is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. ... // Headline text HEY!! HOW ARE YOU ALL?? Its nice of you to come read this page. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequently refined in terms of other characteristics. ... In astronomy, color index is a simple numerical expression that determines the color of an object, which in the case of a star gives its temperature. ... In astronomy, color index is a simple numerical expression that determines the color of an object, which in the case of a star gives its temperature. ... Most stars are of almost constant luminosity. ... This article does not cite its references or sources. ... Radial velocity is the velocity of an object in the direction of the line of sight. ... kilometre per second is an SI derived unit of both speed (scalar) and velocity (vector), signified by the symbol km/s or km s-1. ... The proper motion of a star is the motion of the position of the star in the sky (the change in direction in which we see it, as opposed to the radial velocity) after eliminating the improper motions of the stars, which affect their measured coordinates but are not real... A milliarcsecond (m, mas) , or a thoundsanth of an arcsecond. ... A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... A milliarcsecond (m, mas) , or a thoundsanth of an arcsecond. ... A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... Parallax (Greek: παραλλαγή (parallagé) = alteration) is the change of angular position of two stationary points relative to each other as seen by an observer, due to the motion of an observer. ... A milliarcsecond (m, mas) , or a thoundsanth of an arcsecond. ... The distance between two points is the length of a straight line segment between them. ... A light year, abbreviated ly, is the distance light travels in one year: roughly 9. ... Stellar parallax motion The parsec (symbol pc) is a unit of length used in astronomy. ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standard luminosity distance away from us (in the absence of interstellar extinction!). It allows the overall brightnesses of objects to be compared without regard to distance. ... Artists impression of a binary star system consisting of a black hole, with an accretion disc around it, and a main sequence star. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... In geometry, the semi-major axis (also semimajor axis) a applies to ellipses and hyperbolas. ... In astrodynamics, under standard assumptions any orbit must be of conic section shape. ... Inclination in general is the angle between a reference plane and another plane or axis of direction. ... An orbital node is one of the two points where an inclined orbit crosses a plane of reference (e. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. ... Mass is a property of a physical object that quantifies the amount of matter and energy it contains. ... In astronomy, the solar mass is a unit of mass used to express the mass of stars and larger objects such as galaxies. ... In classical geometry, a radius of a circle or sphere is any line segment from its center to its boundary. ... In astronomy, the solar radius is a unit of length used to express the size of stars and larger objects such as galaxies. ... Luminosity has different meanings in several different fields of science. ... The solar luminosity, , is a unit of luminosity (power emitted in the form of photons) conventionally used by astronomers to give the luminosities of stars. ... Temperature is also the name of a song by Sean Paul. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ... In astronomy, the metallicity of an object is the proportion of its matter made up of chemical elements other than hydrogen and helium. ... Rotation of a plane, seen as the rotation of the terrain relative to the plane (exposure time 1. ... The Pleiades star cluster A star is a massive, compact body of plasma in outer space that is currently producing or has produced energy through nuclear fusion. ... A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... In astronomy, many stars are referred to simply by catalogue numbers. ... In astronomy, many stars are referred to simply by catalogue numbers. ... In astronomy, many stars are referred to simply by catalogue numbers. ... In astronomy, many stars are referred to simply by catalogue numbers. ... The Henry Draper Catalogue is an astronomy catalogue with astrometric and spectroscopic data about more than 225,000 stars. ... In astronomy, many stars are referred to simply by catalogue numbers. ... The Smithsonian Astrophysical Observatory (SAO) is a research institute of the Smithsonian Institution headquartered in Cambridge, Massachusetts, where it is joined with the Harvard College Observatory (HCO) to form the Harvard-Smithsonian Center for Astrophysics (CfA). ... In astronomy, many stars are referred to simply by catalogue numbers. ... The Pleiades star cluster A star is a massive, compact body of plasma in outer space that is currently producing or has produced energy through nuclear fusion. ... Orion is a remarkable constellation, visible from most places on the globe at one time or another during the year. ... Cepheus is a northern constellation named after King Cepheus in Greek mythology, and is considered to represent a king. ...

Gamma Cephei is a binary star approximately 50 light years from Earth, with an apparent magnitude of 3.22. The larger and brighter star is a stellar class K1 IV orange subgiant star. The smaller is a red dwarf in a poorly studied orbit: the current best guess is that it orbits eccentrically from 10 to 29 AU over the course of 70 yrs ± 16 yrs, with an eccentricity of 0.439 ± 0.06 (Cochran et al 2002). Artists impression of a binary star system consisting of a black hole, with an accretion disc around it, and a main sequence star. ... A light year, abbreviated ly, is the distance light travels in one year: roughly 9. ... // Headline text HEY!! HOW ARE YOU ALL?? Its nice of you to come read this page. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequenly refined in terms of other characteristics. ... Subgiant star is a class of stars that are brighter than normal main sequence (dwarf) stars, but not as bright as true giant stars. ... This article describes the British science fiction comedy television series. ... The astronomical unit (AU or au or a. ...

Gamma Cephei is the naked-eye star that will follow Polaris as the Earth's northern pole star, due to the precession of the equinoxes. Alrai will become closer to the northern celestial pole than Polaris around 3000 AD, and be at its closest approach around 4000 AD. The "title" will pass to ι Cephei some time around 5200 AD. Polaris (α UMi / α Ursae Minoris / Alpha Ursae Minoris) is the brightest star in the constellation Ursa Minor. ... Earth (often referred to as The Earth) is the third planet in the solar system in terms of distance from the Sun, and the fifth in order of size. ... For other uses of the words Pole star and Polestar see Polestar (disambiguation). ... Precession of the equinoxes refers to the precession of the Earths axis of rotation. ... The two celestial poles are the imaginary points where the Earths spin axis intersects the imaginary rotating sphere of gigantic radius, called the celestial sphere. ... The 30th century comprises the years 2901-3000 (Gregorian calendar or Common Era). ... For the meaning in finance, see futures contract. ... (4th millennium – 5th millennium – 6th millennium – other millennia) The fifth millennium is a period of time which will begin on January 1, 4001 and will end on December 31, 5000. ...

The traditional name derives from the Arabic الراعي ar-rā‘ī, meaning "the shepherd". Confusingly, the star β Ophiuchi is sometimes also called Alrai, but it is more commonly known as Cebalrai or Kelb Alrai, meaning "shepherd's dog". The Arabic language (Arabic: ‎ transliterated: ), or simply Arabic (Arabic: ‎ transliterated: ), is the largest member of the Semitic branch of the Afro-Asiatic language family (classification: South Central Semitic) and is closely related to Hebrew and Aramaic. ... Cebalrai (arab. ... This article needs to be cleaned up to conform to a higher standard of quality. ... This article needs to be cleaned up to conform to a higher standard of quality. ...

Planetary system

In 1989, a planet orbiting Gamma Cephei A was announced by Anthony Lawton and P. Wright. Its existence was also suspected by a Canadian team led by Bruce Campbell and Gordon Walker in the early 1990s. This would have been the first confirmed extrasolar planet, and it was hypothesized based on the same radial velocity technique later used successfully by others. However, the claim was retracted in 1992 due to the quality of the data not being good enough to make a solid discovery. But in 2002, evidence of the planet was considerably strengthened by the new measurements at the McDonald Observatory. 1989 (MCMLXXXIX) was a common year starting on Sunday of the Gregorian calendar. ... Radial velocity is the velocity of an object in the direction of the line of sight. ... 1992 (MCMXCII) was a leap year starting on Wednesday. ... For album titles with the same name, see 2002 (album). ... Aerial view of the McDonald Observatory. ...

Atmospheric characteristics Atmospheric pressure 70 kPa Hydrogen ~86% Helium ~14% Methane 0. ... Water, Rabbit, and Deer: three of the 20 day symbols in the Aztec calendar, from the Aztec Sun Stone. ... The astronomical unit (AU or au or a. ... Gamma Cephei Ab is an extrasolar planet orbiting Gamma Cephei A every two years. ...

See also

• Iota Horologii
• Gliese 777

Iota Horologii (also called HR 810 / ι Hor) is a Sun-like star about 50 ly. ... Gliese 777 (Gl 777) is a 6th magnitude star in the constellation Cygnus. ...

References

• Hatzes et al. (2003). "A Planetary Companion to Gamma Cephei A". The Astrophysical Journal 599: 1383-1394.

The Astrophysical Journal is one of the foremost research journals devoted to recent developments, discoveries, and theories in astronomy and astrophysics. ...

External links

• McDonald Observatory: Planet Search finds first planet orbiting close-in binary star
• A Planetary Companion to the Binary Star Gamma Cephei
• SolStation: Errai 2
• Extrasolar Planets Encyclopaedia: Gamma Cephei + Gamma Cephei b
• Extrasolar Visions: Gamma Cephei A + Gamma Cephei Ab + Gamma cephei B