Lambda Tauri
Encyclopedia
Lambda Tauri is a triple star system in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

 Taurus
Taurus (constellation)
Taurus is one of the constellations of the zodiac. Its name is a Latin word meaning 'bull', and its astrological symbol is a stylized bull's head:...

. The primary component, Lambda Tauri A, is a blue-white B-type
Stellar classification
In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...

 main sequence dwarf
Main sequence
The main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell...

 with a mean apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...

 of +3.41. It has a luminosity
Luminosity
Luminosity is a measurement of brightness.-In photometry and color imaging:In photometry, luminosity is sometimes incorrectly used to refer to luminance, which is the density of luminous intensity in a given direction. The SI unit for luminance is candela per square metre.The luminosity function...

 of about 4,000 times that of the Sun and a radius of 6.6 times solar. The companion is a white A-type subgiant of 5.5 solar radii and 95 solar luminosities. They orbit around a common centre of gravity once every 3.95 days. The spatial separation between these two stars is measured at 0.1 astronomical unit
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....

.

Because the system is an eclipsing binary its brightness varies from magnitude +3.37 to +3.91 as first one star and then the other pass in front of its companion. The system has a third, dimmer star with an orbital period of 33 days. The Lambda Tauri system is approximately 370 light years
Light Years
Light Years is the seventh studio album by Australian recording artist Kylie Minogue. It was released on 25 September 2000 by Parlophone and Mushroom Records. The album's style was indicative of her return to "mainstream pop dance tunes"....

 from Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

.

It, along with δ Librae
Delta Librae
Delta Librae is a variable star in the constellation Libra. It has the proper name Zuben Elakribi. With μ Vir it forms one of the Akkadian lunar mansions Mulu-izi ....

, was the first star on which
rotational line broadening
was observed, by Frank Schlesinger
Frank Schlesinger
Frank Schlesinger was an American astronomer. His work concentrated on using photographic plates rather than direct visual studies for astronomical research.-Biography:...

 in 1909.

Name

E.B Knobel, in the journal titled On a catalogue of stars in the Calendarium of Al Achsasi Al Mouakket, told that this star was designated as Sadr al Tauri which was translated in Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

as Pectus Tauri, meaning the bull chest
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