Beta Draconis
Encyclopedia
Beta Draconis (Beta Dra, β Draconis, β Dra) is the third brightest star
in the constellation
of Draco
. It has the traditional name Rastaban, which has also been used for Gamma Draconis.
It is a G-type giant star
, with spectral class
G2 and an apparent visual magnitude of approximately 2.79. Its distance from the Sun
is around 360 light years
. It is a binary star
, with a binary star designation of ADS
10611, in which the supergiant is orbited by a dwarf companion once every four millennia or so.
phrase ra's ath-thu'ban ("head of the serpent") is less commonly written Rastaben. It is also known as Asuia and Alwaid, the latter meaning "who is to be destroyed," though some trace it to Arabic al'awwad ("the lute player"). It is part of the asterism
of the Mother Camels
(Arabic al'awa'id), along with γ Dra (Eltanin), μ Dra
(Erakis) ν Dra
(Kuma) and ξ Dra
(Grumium), which was later known as the Quinque Dromedarii.
In Chinese
, , meaning Celestial Flail
, refers to an asterism consisting of β Draconis, ξ Draconis
, ν Draconis
, γ Draconis and ι Herculis
. Consequently, β Draconis itself is known as
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....
of Draco
Draco (constellation)
Draco is a constellation in the far northern sky. Its name is Latin for dragon. Draco is circumpolar for many observers in the northern hemisphere...
. It has the traditional name Rastaban, which has also been used for Gamma Draconis.
It is a G-type giant star
Giant star
A giant star is a star with substantially larger radius and luminosity than a main sequence star of the same surface temperature. Typically, giant stars have radii between 10 and 100 solar radii and luminosities between 10 and 1,000 times that of the Sun. Stars still more luminous than giants are...
, with spectral class
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...
G2 and an apparent visual magnitude of approximately 2.79. Its distance from the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
is around 360 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"....
. It is a binary star
Binary star
A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
, with a binary star designation of ADS
Aitken Double Star Catalogue
The Aitken Double Star Catalogue, or ADS, is a star catalogue of double stars. It was compiled by Robert Grant Aitken and published in 1932 in two volumes, under the name New general catalogue of double stars within 120° of the North Pole. It contains measurements of 17,180 double stars north of...
10611, in which the supergiant is orbited by a dwarf companion once every four millennia or so.
Name
The traditional name, from the ArabicArabic language
Arabic is a name applied to the descendants of the Classical Arabic language of the 6th century AD, used most prominently in the Quran, the Islamic Holy Book...
phrase ra's ath-thu'ban ("head of the serpent") is less commonly written Rastaben. It is also known as Asuia and Alwaid, the latter meaning "who is to be destroyed," though some trace it to Arabic al'awwad ("the lute player"). It is part of the 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,...
of the Mother Camels
Mother Camels
The Arabs did not see the constellation Draco as it is now, but in fact they had three sectors in this constelations. the main sector or part was the protecting mother camels, the other parts is the star μ Dra which was called the dancer الراقص and the other part is the wolfs nails or fingerprint...
(Arabic al'awa'id), along with γ Dra (Eltanin), μ Dra
Mu Draconis
Mu Draconis is a binary star with a combined magnitude of 4.92m located approximately 85 light years from the Solar System, near the head of the constellation Draco. The component stars are nearly identical yellow-white stars in a tight orbit...
(Erakis) ν Dra
Nu Draconis
Nu Draconis is a double star in the constellation Draco. The respective components are designated ν1 Draconis and ν2 Draconis...
(Kuma) and ξ Dra
Xi Draconis
Xi Draconis is a star in the constellation Draco. It has the traditional name Grumium or Genam.This star, along with β Dra , γ Dra , μ Dra and ν Dra were Al ʽAwāïd, "the Mother Camels", which was later known as the Quinque Dromedarii.In Chinese, , meaning Celestial Flail, refers to an asterism...
(Grumium), which was later known as the Quinque Dromedarii.
In Chinese
Chinese language
The Chinese language is a language or language family consisting of varieties which are mutually intelligible to varying degrees. Originally the indigenous languages spoken by the Han Chinese in China, it forms one of the branches of Sino-Tibetan family of languages...
, , meaning Celestial Flail
Purple Forbidden enclosure
The Purple Forbidden enclosure is one of the San Yuan or Three enclosures. Stars and constellations of this group lie near the north celestial pole and visible all year from temperate latitudes in the Northern Hemisphere.-Asterisms:The asterisms are :...
, refers to an asterism consisting of β Draconis, ξ Draconis
Xi Draconis
Xi Draconis is a star in the constellation Draco. It has the traditional name Grumium or Genam.This star, along with β Dra , γ Dra , μ Dra and ν Dra were Al ʽAwāïd, "the Mother Camels", which was later known as the Quinque Dromedarii.In Chinese, , meaning Celestial Flail, refers to an asterism...
, ν Draconis
Nu Draconis
Nu Draconis is a double star in the constellation Draco. The respective components are designated ν1 Draconis and ν2 Draconis...
, γ Draconis and ι Herculis
Iota Herculis
Iota Herculis is a fourth-magnitude star in the constellation Hercules. The luminary shares an etymological similarity with the star Rigel in the constellation of Orion, as both stars refer to one of the feet of each mythological hero.In Chinese, , meaning Celestial Flail, refers to an asterism...
. Consequently, β Draconis itself is known as
External links
- Dibon-Smith, Richard (1992). StarList 2000: A Quick Reference Star Catalog for Astronomers. New York: John Wiley & Sons. ISBN 0-471-55895-8