Eta Draconis
Encyclopedia
Eta Draconis 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....

 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...

. Eta Draconis 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...

 +2.73 (third-magnitude) and is a yellow giant
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...

 variable star
Variable star
A star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...

 belonging to 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...

 G8III. The 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 Eta Draconis is neary 50 times that of 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...

. It is approximately 88 light years 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...

.

Name

η Draconis, together ζ Dra
Zeta Draconis
Zeta Draconis is a star in the constellation Draco. It shares the Arabic name Al dhi'bah with several other stars in the constellation, and, together with Eta Draconis, it also shares the name Al dhibain...

 (Al Dhibah) and were Al Dhīʼbain, the Duo Lupi in Arabic, of early works, the Two Hyaenas or Wolves, lying in wait for the Camel's Foal, the little star Al Rubaʽ, protected by 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...

.

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 Left Wall of Purple Forbidden Enclosure
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 η Draconis, ι Draconis
Iota Draconis
Iota Draconis is an orange giant star located away in the constellation Draco. A visually unremarkable star of apparent magnitude 3.31, it has recently been discovered to have a planet.-Name:...

, θ Draconis
Theta Draconis
Theta Draconis is a fourth-magnitude star in the constellation Draco.-Chinese name:In Chinese, , meaning Left Wall of Purple Forbidden Enclosure, refers to an asterism consisting of θ Draconis, ι Draconis, η Draconis, ζ Draconis, υ Draconis, 73 Draconis, γ Cephei and 23 Cassiopeiae...

, ζ Draconis
Zeta Draconis
Zeta Draconis is a star in the constellation Draco. It shares the Arabic name Al dhi'bah with several other stars in the constellation, and, together with Eta Draconis, it also shares the name Al dhibain...

, υ Draconis, 73 Draconis, γ Cephei
Gamma Cephei
Gamma Cephei , traditionally named Errai, Er Rai, and or Alrai, is a binary star system approximately 45 light-years away in the constellation of Cepheus. Gamma Cephei contains an apparent magnitude of 3.22. The visible part of the system is a stellar class K1III-IV orange subgiant star on its...

 and 23 Cassiopeiae. Consequently, η Draconis itself is known as , representing , meaning The Second Premier. Possibly, 右樞 (Shǎozǎi) is westernized into Hea Tsae by R.H. Allen with meaning "the Lowest Steward" but it was for θ Dra
Theta Draconis
Theta Draconis is a fourth-magnitude star in the constellation Draco.-Chinese name:In Chinese, , meaning Left Wall of Purple Forbidden Enclosure, refers to an asterism consisting of θ Draconis, ι Draconis, η Draconis, ζ Draconis, υ Draconis, 73 Draconis, γ Cephei and 23 Cassiopeiae...

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