Zeta Draconis
Encyclopedia
Zeta Draconis is a star
in the constellation
Draco
. It shares the Arabic
name Al dhi'bah ('the hyenas') with several other stars in the constellation, and, together with Eta Draconis
, it also shares the name Al dhibain. It is also known as Nodus III (Third Knot, the knot being a loop in the tail of Draco).
In Chinese
, , meaning Left Wall of Purple Forbidden Enclosure
, refers to an asterism consisting of ζ Draconis, ι Draconis
, η Draconis
, θ Draconis
, υ Draconis, 73 Draconis, γ Cephei
and 23 Cassiopeiae. Consequently, ζ Draconis itself is known as , representing , meaning The First Minister. 上弼 (Shǎngbì) is westernized into Shang Pih by R.H. Allen with meaning "the Higher Minister".
with an apparent magnitude
of +3.17 and a spectral class
of B9. The temperature of the star's photosphere
is nearly 13,400 K. The minimum rotation velocity
at the equator is 55 km/s. Zeta Draconis is an estimated 340 light years from the Earth
.
The north ecliptic pole
is located at right ascension
18h and declination
+66.5°. This is located roughly mid-way between Delta Draconis
and Zeta Draconis.
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...
. It shares the Arabic
Arabic 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...
name Al dhi'bah ('the hyenas') with several other stars in the constellation, and, together with Eta Draconis
Eta Draconis
Eta Draconis is a star in the constellation Draco. Eta Draconis has apparent magnitude +2.73 and is a yellow giant variable star belonging to spectral class G8III. The luminosity of Eta Draconis is neary 50 times that of the Sun...
, it also shares the name Al dhibain. It is also known as Nodus III (Third Knot, the knot being a loop in the tail of Draco).
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 ζ 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:...
, η Draconis
Eta Draconis
Eta Draconis is a star in the constellation Draco. Eta Draconis has apparent magnitude +2.73 and is a yellow giant variable star belonging to spectral class G8III. The luminosity of Eta Draconis is neary 50 times that of the Sun...
, 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...
, 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, ζ Draconis itself is known as , representing , meaning The First Minister. 上弼 (Shǎngbì) is westernized into Shang Pih by R.H. Allen with meaning "the Higher Minister".
Properties
Zeta Draconis is a giant starGiant 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 an 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 +3.17 and a 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...
of B9. The temperature of the star's photosphere
Photosphere
The photosphere of an astronomical object is the region from which externally received light originates. The term itself is derived from Ancient Greek roots, φῶς, φωτός/phos, photos meaning "light" and σφαῖρα/sphaira meaning "sphere", in reference to the fact that it is a spheric surface perceived...
is nearly 13,400 K. The minimum rotation velocity
Stellar rotation
Stellar rotation is the angular motion of a star about its axis. The rate of rotation can be measured from the spectrum of the star, or by timing the movements of active features on the surface....
at the equator is 55 km/s. Zeta Draconis is an estimated 340 light years from the 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...
.
The north ecliptic pole
Ecliptic pole
The ecliptic pole is the point on the celestial sphere where the sphere meets the imaginary line perpendicular to the ecliptic plane, the path the Earth travels on its orbit around the Sun.There are two ecliptic poles:...
is located at right ascension
Right ascension
Right ascension is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. The other coordinate is the declination.-Explanation:...
18h and declination
Declination
In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. Declination is measured in degrees north and...
+66.5°. This is located roughly mid-way between Delta Draconis
Delta Draconis
Delta Draconis is a yellow star in the constellation Draco. It has the traditional names Aldib, Altais and Nodus Secundus....
and Zeta Draconis.