Ursa Major

Epsilon Ursae Majoris (ε UMa / ε Ursae Majoris) is the brightest star in the constellation Ursa Major (despite its Bayer designation being merely "epsilon"), and at magnitude 1.76 is the thirty-first brightest star in the sky. It also has the traditional name Alioth (from the Arabic word alyat—fat tail of a sheep). 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. ... Ursa Major (Ursa Maior in Latin) is a constellation visible throughout the year in the northern hemisphere. ... Right ascension (RA; symbol α: Greek letter alpha; celestial longitude) 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. ... The apparent magnitude (m) of a star, planet or other celestial body is a measure of its apparent brightness as seen by an observer on Earth. ... 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 nearly 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. ... 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. ... In classical geometry, a radius of a circle or sphere is any line segment with one endpoint on the circle (i. ... 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 the physical property of a system which underlies the common notions of hot and cold; the material with the higher temperature is said to be hotter. ... 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. ... STAR is an acronym for: Scientific and Technological Advanced Research Labs, a fictional research organization in the DC Comics universe. ... 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. ... Image File history File links Download high resolution version (1548x627, 72 KB) Description: Source: based upon Image:Ursa major constellation map. ... Image File history File links Download high resolution version (1548x627, 72 KB) Description: Source: based upon Image:Ursa major constellation map. ... STAR is an acronym for: Scientific and Technological Advanced Research Labs, a fictional research organization in the DC Comics universe. ... Orion is a remarkable constellation, visible from most places on the globe at one time or another during the year. ... Ursa Major (Ursa Maior in Latin) is a constellation visible throughout the year in the northern hemisphere. ... Many of the brighter stars are given names which are known as Bayer designations. ... The apparent magnitude (m) of a star, planet or other celestial body is a measure of its apparent brightness as seen by an observer on Earth. ... Bright stars can be bright because they produce more light, because they are closer to us, or both. ...

It is the star in the tail of the bear closest to its body, and thus the star in the handle of the Big Dipper closest to the bowl. It is also a member of the large and diffuse Ursa Major moving group. Historically, the star was frequently used in maritime navigation.^[1] Ursa Major is a constellation visible throughout the year in the northern hemisphere. ... In 1869, Richard A. Proctor noticed that, except for Dubhe and Alkaid, the stars of the Big Dipper all have proper motions heading towards a common point in Sagittarius. ...

According to Hipparcos, Alioth is 81 light years (25 parsecs) from Earth. Its spectral type is A0p; the "p" stands for peculiar, as the spectrum of its light is quite odd, of a kind characteristic of an Alpha2 Canum Venaticorum variable. Alioth, as a representative of this type, is believed to look the way it does because of two interacting processes: first, the star's strong magnetic field separating different elements salting the star's hydrogen fuel, then a rotation axis at an angle to the magnetic axis spinning different bands of magnetically sorted elements into the line of sight between Alioth and the Earth. The intervening elements react differently at different frequencies of light as they whip in and out of view, causing Alioth to have very strange spectral lines that fluctuate over a period of 5.1 days. In the case of Alioth, the rotational and magnetic axes are at almost 90 degrees to one another; in the map of Alioth linked below, note how the darker (more dense) regions of chromium form a band at right angles to the equator. Hipparcos (for High Precision Parallax Collecting Satellite) was an astrometry mission of the European Space Agency (ESA) dedicated to the measurement of stellar parallax and the proper motions of stars. ... 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. ... Earth is the third planet from the Sun. ... 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. ... Legend: γ = Gamma rays HX = Hard X-rays SX = Soft X-Rays EUV = Extreme ultraviolet NUV = Near ultraviolet Visible light NIR = Near infrared MIR = Moderate infrared FIR = Far infrared Radio waves: EHF = Extremely high frequency (Microwaves) SHF = Super high frequency (Microwaves) UHF = Ultrahigh frequency VHF = Very high frequency HF = High frequency... Alpha2 Canum Venaticorum variables are main sequence variable stars of spectral class B8p to A7p. ... It has been suggested that Magnetic field density be merged into this article or section. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ... General Name, Symbol, Number chromium, Cr, 24 Chemical series transition metals Group, Period, Block 6, 4, d Appearance silvery metallic Atomic mass 51. ...

For its type, Alioth has a relatively weak magnetic field (15 times weaker than α CVn's), but it is still 100 times stronger than that of the Earth.

References

1. ^{^} This article incorporates content from the 1728 Cyclopaedia, a publication in the public domain.

Cyclopaedia; or an Universal Dictionary of Arts and Sciences (folio, 2 vols. ... The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ...

External links

• Chromium distribution on Alioth