Eta Ursae Majoris
Encyclopedia
Eta Ursae Majoris (η UMa, η Ursae Majoris) is a star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

 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....

 Ursa Major
Ursa Major
Ursa Major , also known as the Great Bear, is a constellation visible throughout the year in most of the northern hemisphere. It can best be seen in April...

. It has the traditional names Alkaid (or Elkeid) and Benetnash (Benetnasch).

Alkaid is the most eastern (leftmost) star in the Big Dipper
Big Dipper
The Plough, also known as the Big Dipper or the Saptarishi , is an asterism of seven stars that has been recognized as a distinct grouping in many cultures from time immemorial...

 (Plough) asterism
Asterism (astronomy)
In astronomy, an asterism is a pattern of stars recognized on Earth's night sky. It may form part of an official constellation, or be composed of stars from more than one. Like constellations, asterisms are in most cases composed of stars which, while they are visible in the same general direction,...

. However, unlike most stars of the Big Dipper, it is not a member of the Ursa Major moving group
Ursa Major Moving Group
The Ursa Major Moving Group, also known as Collinder 285 or Ursa Major association, is a nearby stellar moving group, a set of stars with common velocities in space and thought to have a common origin. Its core is located roughly 80 light years away...

.

Alkaid has 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...

 +1.9, making it the 35th brightest star in the sky. It is a young, bluish-white main sequence
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...

 star of spectral class B3 V. At 20,000 kelvin
Kelvin
The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...

s it is one of the hotter stars visible with the naked eye.

The name derives from the Arabic phrase meaning "The leader of the daughters of the bier
Bier
A bier is a stand on which a corpse, coffin or casket containing a corpse, is placed to lie in state or to be carried to the grave.In Christian burial, the bier is often placed in the centre of the nave with candles surrounding it, and remains in place during the funeral.The bier is a flat frame,...

" ( ). The daughters of the bier, i.e. the mourning maidens, are the three stars of the handle of the Big Dipper, Alkaid, Mizar
Mizar (star)
The Mizar–Alcor stellar sextuple system consists of the quadruple system Mizar and the binary system Alcor.- Description :Mizar is a quadruple system of two binary stars in the constellation Ursa Major and is the second star from the end of the Big Dipper's handle. Its apparent magnitude is 2.23...

, and Alioth
Epsilon Ursae Majoris
Epsilon Ursae Majoris is the brightest star in the constellation Ursa Major , and at magnitude 1.76 is the thirty-first brightest star in the sky...

; while the four stars of the bowl, Megrez
Delta Ursae Majoris
Delta Ursae Majoris is a star in the constellation Ursa Major. It has the traditional names Megrez , from the al-maghriz "the base [of the bear's tail]", and Kaffa....

, Phecda
Gamma Ursae Majoris
Gamma Ursae Majoris is a star in the constellation Ursa Major. It has the traditional name Phad, or Phecda, from the Arabic phrase فخذ الدب "fakhð ad-dubb" ....

, Merak
Beta Ursae Majoris
Beta Ursae Majoris is a star in the constellation of Ursa Major. It has the traditional name Merak.It is more familiar to northern hemisphere observers as one of the "pointer stars" in the Big Dipper, and a straight line connecting it with nearby Alpha Ursae Majoris extends to Polaris, the north...

, and Dubhe, are the bier.

Other name

It is known as 北斗七 (the Seventh Star of the Northern Dipper) or 搖光 (the Star of Twinkling Brilliance) in Chinese

In Japan, Alkaid in known as Hagunsei ("the military breaking star" or "most corner star"). Both meanings come from ancient China's influence in Japan. In Chinese fortune-telling, north is believe to be very unlucky direction. Northwest is even worse. Hunters and soldiers traditionally did not point guns and weapons in the direction of Hagunsei

Namesakes

USS Alkaid (AK-114)
USS Alkaid (AK-114)
USS Alkaid was an Crater-class cargo ship commissioned by the U.S. Navy for service in World War II, named after Alkaid, the star in Big Dipper asterism or constellation Ursa Major. She was responsible for delivering troops, goods and equipment to locations in the war zone.SS William G...

 was a United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 Crater class cargo ship
Crater class cargo ship
Crater-class cargo ship is a category of freighter that was constructed for use by the United States Navy during World War II under Maritime Commission EC2-S-C1 type....

named after the star.

External links

  • Alkaid at Jim Kaler's Stars website
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK