Beta Librae (β Lib / β Librae) is the brightest star in the constellation Libra. It also has the traditional name Zuben Eschamali (pronounced zoo-ben-es-sha-mali) and the Latin name Lanx Australis. The name Zuben Eschamali is derived from an Arabic phrase Al Zuban al Shamaliyyah meaning "the northern claw".^[1] This article is about the astronomical object. ... This article or section does not cite its references or sources. ... Libra (, and Latin for balance) is a constellation of the zodiac. ... Latin is an ancient Indo-European language originally spoken in Latium, the region immediately surrounding Rome. ...

Description

Beta Librae is a blue dwarf star of spectral type B8 (main sequence star), a little less evolved than Sirius. It has apparent magnitude 2.7. Blue dwarfs are main sequence stars of spectral type O. A typical type O dwarf has a mass of 50 Suns and is tens of thousands of times more luminous than the Sun. ... 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. ... For other uses, see Sirius (disambiguation). ... // Headline text HEY!! HOW ARE YOU ALL?? Its nice of you to come read this page. ...

At a distance of 160 light years from Earth, it is about 130 times more luminous than the Sun and has a surface temperature of 12,000 kelvins, double that of the Sun. This high temperature produces light with a simple spectrum, making it ideal for examining the interstellar gas and dust between us and the star. Like many stars of its kind, it is spinning rapidly, over 100 times faster than the Sun. This type of hydrogen-fusing star often appears blue-white, but Beta Librae is often described as greenish, the only greenish star visible to the naked eye.^[2] A light-year or lightyear, symbol ly, is a unit of length. ... Earth (IPA: , often referred to as the Earth, Terra, the World or Planet Earth) is the third planet in the solar system in terms of distance from the Sun, and the fifth largest. ... The Kelvin scale is a thermodynamic (absolute) temperature scale where absolute zero—the lowest possible temperature where nothing could be colder and no heat energy remains in a substance—is defined as zero kelvin (0 K). ... In most modern usages of the word spectrum, there is a unifying theme of between extremes at either end. ...

The small periodic variations in the magnitude of the Beta Librae imply the presence of a companion star which is not directly observable from earth.^[3]

Data from the Hipparcos catalogue:^[4] 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. ...

• Bayer name for the star: Beta Librae
• Proper name of the star: Zubeneschamali
• Right Ascension in hours and minutes for epoch 2000: 15h 17m
• Declination in degrees for epoch 2000: −9°22'57"
• Galactic longitude of the star: 352.0
• Galactic latitude of the star: +39.2
• Spectral classification: B8V
• Visual magnitude of the star: 2.61
• Absolute magnitude of the star: -0.84
• The Hipparcos parallax of the star (x1000): 20.38
• The error in the parallax (x1000): 0.87
• The distance in light years (=3.2616/parallax): 160

Many of the brighter stars are given names which are known as Bayer designations. ... Equatorial Coordinates Right ascension (abbrev. ... 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 anisotropy of the star density in the night sky makes the galactic coordinate system very useful for coordinating surveys, both those which require high densities of stars (at low galactic latitudes) and those which require a low density of stars (at high galactic latitudes) Many galaxies, including the Milky... The anisotropy of the star density in the night sky makes the galactic coordinate system very useful for coordinating surveys, both those which require high densities of stars (at low galactic latitudes) and those which require a low density of stars (at high galactic latitudes) Many galaxies, including the Milky... 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. ... // Headline text HEY!! HOW ARE YOU ALL?? Its nice of you to come read this page. ... 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. ... 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 or lightyear, symbol ly, is a unit of length. ...

History

According to Eratosthenes Beta Librae was observed to be brighter than Antares. Ptolemy, three hundred and fifty years later, said it was as bright as Antares. The discrepancy may be due to Antares becoming brighter, but this is not known for certain. It could simply be caused by Beta Librae being a variable star with a variability of 0.03 of a magnitude.^[1] Eratosthenes (Greek ; 276 BC - 194 BC) was a Hellenistic mathematician, geographer and astronomer. ... This article or section does not cite its references or sources. ... A medieval artists rendition of Claudius Ptolemaeus Claudius Ptolemaeus (Greek: ; c. ... Most stars are of almost constant luminosity. ...

References

1. ^ ^{a b} AAS (2006). LIBRA – A Balanced View. Auckland Astronomical Society. Retrieved on 2006-07-03.
2. ^ Jim Kaler (2006). Zubeneschamali. Stars. Retrieved on 2006-07-03.
3. ^ Mark Fisher (1999-2006). Zuben Elschemali. The Electronic Sky. Retrieved on 2006-07-03.
4. ^ Dan McGuire (1997). The Brightest Stars (.pdf). Retrieved on 2006-07-03.

2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... July 3 is the 184th day of the year (185th in leap years) in the Gregorian calendar, with 181 days remaining. ... 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... July 3 is the 184th day of the year (185th in leap years) in the Gregorian calendar, with 181 days remaining. ... 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... July 3 is the 184th day of the year (185th in leap years) in the Gregorian calendar, with 181 days remaining. ... 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... July 3 is the 184th day of the year (185th in leap years) in the Gregorian calendar, with 181 days remaining. ...

External links

• for more examples of Arabic star names (such as Rigel, Fomalhaut, Algol, and Betelgeuse) see

Moh'd Odeh (1998-2006). Arabic Star Names. Islamic Crescents' Observation Project. Retrieved on 2006-07-03.