Alpha Coronae Borealis (α CrB / α Coronae Borealis) is a binary star in the constellation Corona Borealis. It also has the traditional names Gemma or Alphekka or Alphecca. In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. ... Orion is a remarkable constellation, visible from most places on the globe at one time or another during the year. ... Corona Borealis (Latin for northern crown) is a small northern constellation whose main stars form a semicircular arc. ... 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. ... Shanil Davendra Singh rules 4 life! ... Shanil Davendra Singh rules 4 life! ... Most stars are of almost constant luminosity. ... Animation showing how an eclipsing binary stars light intensity changes as they orbit An eclipsing binary star is a binary star in which the orbit plane of the two stars lies so nearly in the line of sight of the observer that the components undergo mutual eclipses. ... 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. ... 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. ... Mass is a property of a physical object that quantifies the amount of matter 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. ... RADIUS (Remote Authentication Dial In User Service) is an AAA (authentication, authorization and accounting) protocol for applications such as network access or IP mobility. ... 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 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. ... 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. ... A binary star system consists of two stars both orbiting around their barycenter. ... Orion is a remarkable constellation, visible from most places on the globe at one time or another during the year. ... Corona Borealis (Latin for northern crown) is a small northern constellation whose main stars form a semicircular arc. ...

α CrB is an eclipsing binary system similar to Algol (β Per). Its period is 17.36 days, with magnitude varying from +2.16 to +2.30, which is hardly noticeable to the unaided eye. Animation showing how an eclipsing binary stars light intensity changes as they orbit An eclipsing binary star is a binary star in which the orbit plane of the two stars lies so nearly in the line of sight of the observer that the components undergo mutual eclipses. ... ALGOL (short for ALGOrithmic Language) is a family of imperative computer programming languages originally developed in the mid 1950s which became the de facto standard way to report algorithms in print for almost the next 30 years. ...

α CrB is believed to be a stream star member of the Ursa Major Moving Group. The Ursa Major Moving Group is the closest moving group to Earth, with its core being located roughly 80 light years away. ...

The name Gemma is Latin for "jewel". The other traditional name comes from Arabic al-fakkah, "the broken" (ring of stars), from فكّ fakk "unsealed"). In astrology it is one of the Behenian fixed stars and has the symbol . Latin was the language originally spoken in the region around Rome called Latium. ... The Arabic language (Arabic: ‎ translit: ), or simply Arabic (Arabic: ‎ translit: ), 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. ... The Behenian fixed stars are a selection of fifteen stars considered especially useful for magical applications in the medieval astrology of Europe and the Arab world. ... Image File history File links Agrippa1531_Elpheia. ...

References

• Tomkin, J.; Popper, D. M., 1986, "Rediscussion of eclipsing binaries. XV - Alpha Coronae Borealis, a main-sequence system with components of types A and G", Astronomical Journal, vol. 91, June 1986.