Zeta Draconis (ζ Draconis, abbreviated Zet Dra, ζ Dra) is a

binary star A binary star is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in wh ...

in the northern

circumpolar constellation A circumpolar star is a star that, as viewed from a given latitude on Earth, never sets below the horizon due to its apparent proximity to one of the celestial poles. Circumpolar stars are therefore visible from said location toward the nearest po ...

Draco Draco is the Latin word for serpent or dragon. Draco or Drako may also refer to: People * Draco (lawgiver) (from Greek: Δράκων; 7th century BC), the first lawgiver of ancient Athens, Greece, from whom the term ''draconian'' is derived * ...

. With an

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's lig ...

of +3.17, it is the fifth-brightest member of this generally faint constellation. Its distance from the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

has been measured using the

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...

technique, yielding an estimate of roughly . The two components are designated Zeta Draconis A (formally named Aldhibah , after the traditional name of the system) and B.

Nomenclature

''ζ Draconis'' ( Latinised to ''Zeta Draconis'') is the system's

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. ...

. The designations of the two components as ''Zeta Draconis A'' and ''B'' derives from the convention used by the Washington Multiplicity Catalog (WMC) for

multiple star system A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is generally called a '' star cluster'' or '' galaxy'', although, broadly speaki ...

s, and adopted by the

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

(IAU). Zeta Draconis has the old

Arabic Arabic (, ' ; , ' or ) is a Semitic languages, Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C ...

name الذئب ''al-dhiʼb'' "the wolf" or "the hyena", given in its feminine form "Al Dhiʼbah" (ذئبة) in Allen (1899) (though he mistranslated it as plural "hyenas", which would be الضباع ''al-ḍibāʽ''). It shares the dual form of the name, الذئبين ''al-dhiʼbayn'', with Eta Draconis. It is also known as ''Nodus III'' (Third Knot, the knot being a loop in the tail of Draco). In 2016, the IAU organized a

Working Group on Star Names The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education ...

(WGSN) to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. It approved the name ''Aldhibah'' for the component Zeta Draconis A on 5 September 2017. It also approved the name ''Athebyne'' for Eta Draconis A on the same date. Both are now so included in the List of IAU-approved Star Names. Zeta Draconis is mentioned in

Hindu texts Hindu texts are manuscripts and voluminous historical literature which are related to any of the diverse traditions within Hinduism. A few of these texts are shared across these traditions and they are broadly considered Hindu scriptures. These ...

as ''Tara'' who was a celestial

goddess A goddess is a female deity. In many known cultures, goddesses are often linked with literal or metaphorical pregnancy or imagined feminine roles associated with how women and girls are perceived or expected to behave. This includes themes of s ...

married to Lord

Brhaspati Brihaspati ( sa, बृहस्पति, ), also known as Guru, is a Hindu deity. In the ancient Vedic scriptures of Hinduism, Brihaspati is a deity associated with fire, and the word also refers to a rishi (sage) who counsels the devas (god ...

. A divine epic was played out in the night sky when Lord

Chandra Chandra ( sa, चन्द्र, Candra, shining' or 'moon), also known as Soma ( sa, सोम), is the Hindu god of the Moon, and is associated with the night, plants and vegetation. He is one of the Navagraha (nine planets of Hinduism) and ...

, the moon, lusted after and abducted Tara, the blue pole star of Brhaspati, the planet

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but ...

. By the completion of the epic Tara gives birth to Lord

Budha Budha ( sa, बुध) is a Sanskrit word that connotes the planet Mercury. Budha, in Hindu legends, is also a deity. He is also known as Soumya (Sanskrit: सौम्य, lit. ''son of Moon''), Rauhineya and Tunga and is the Nakshatra lo ...

, or

Mercury Mercury commonly refers to: * Mercury (planet), the nearest planet to the Sun * Mercury (element), a metallic chemical element with the symbol Hg * Mercury (mythology), a Roman god Mercury or The Mercury may also refer to: Companies * Merc ...

. In

Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of ...

, (), meaning '' Left Wall of Purple Forbidden Enclosure'', refers to an asterism consisting of Zeta Draconis,

Iota Draconis Iota Draconis (ι Draconis, abbreviated Iota Dra, ι Dra), also named Edasich , is a star in the northern circumpolar constellation of Draco. A visually unremarkable star of apparent magnitude 3.3, in 2002 it was discovered to have a pl ...

, Eta Draconis,

Theta Draconis Theta Draconis, a name Latinized from θ Draconis, is a binary star system in the northern circumpolar constellation of Draco. It is faintly visible to the naked eye at night with an apparent visual magnitude of 4.12. Parallax measur ...

Upsilon Draconis Upsilon Draconis (υ Dra) is a binary star system in the northern circumpolar constellation of Draco. It is faintly visible to the naked eye with an apparent visual magnitude of 4.83. Based upon an annual parallax shift of 9.48 mas ...

73 Draconis 73 may refer to: * 73 (number) * one of the years 73 BC, AD 73, 1973, 2073 * ''73'' (magazine), a United States-based amateur radio magazine * 73 Best regards, a popular Morse code abbreviation * '' No. 73'', a British 1980s children's TV show *N ...

Gamma Cephei Gamma Cephei (γ Cephei, abbreviated Gamma Cep, γ Cep) is a binary star system approximately 45 light-years away in the constellation of Cepheus. The primary (designated Gamma Cephei A, officially named Errai , the traditional name of ...

and 23 Cassiopeiae. Consequently, the

Chinese name Chinese names or Chinese personal names are names used by individuals from Greater China and other parts of the Chinese-speaking world throughout East and Southeast Asia (ESEA). In addition, many names used in Japan, Korea and Vietnam are often a ...

for Zeta Draconis itself is (, en, the Fourth Star of Left Wall of Purple Forbidden Enclosure), 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 A is a

giant star A giant star is a star with substantially larger radius and luminosity than a main sequence, main-sequence (or ''dwarf'') star of the same effective temperature, surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moo ...

with a

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grati ...

of B6 III. Compared to the Sun, this star is about 2.5 times larger, 3.5 times more massive, and is radiating 148 times as much

luminosity Luminosity is an absolute measure of radiated electromagnetic power (light), the radiant power emitted by a light-emitting object over time. In astronomy, luminosity is the total amount of electromagnetic energy emitted per unit of time by a st ...

. This energy is being emitted from the star's outer envelope at an

effective temperature The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...

of nearly 13,400 K. The

azimuth An azimuth (; from ar, اَلسُّمُوت, as-sumūt, the directions) is an angular measurement in a spherical coordinate system. More specifically, it is the horizontal angle from a cardinal direction, most commonly north. Mathematicall ...

rotation velocity In physics, angular velocity or rotational velocity ( or ), also known as angular frequency vector,(UP1) is a pseudovector representation of how fast the angular position or orientation of an object changes with time (i.e. how quickly an object ...

along the equator is at least 55 km/s. The north

ecliptic pole An orbital pole is either point at the ends of an imaginary line segment that runs through the center of an orbit (of a revolving body like a planet, moon or satellite) and is perpendicular to the orbital plane. Projected onto the celestial sphe ...

is located at

right ascension Right ascension (abbreviated RA; symbol ) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the March equinox to the (hour circle of the) point in question above the earth. When paired w ...

18^h and

declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. Declination's angle is measured north or south of the ...

+66.5°. This is located roughly midway between

Delta Draconis Delta Draconis (δ Draconis, abbreviated Delta Dra, δ Dra), formally named Altais , is a yellow star in the constellation of Draco. It has an apparent visual magnitude of 3.0, making it easily visible to the naked eye. Based on parall ...

and Zeta Draconis. The north ecliptic pole almost coincides with the south celestial pole of

Venus Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never fa ...

; Zeta Draconis is also the north pole star of

References

{{DEFAULTSORT:Zeta Draconis Draco (constellation) Draconis, Zeta B-type giants Aldhibah 083895 Draconis, 22 6396 155763 Durchmusterung objects Binary stars