Alpha Serpentis
Encyclopedia
Alpha Serpentis is a triple star system 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....

 Serpens
Serpens
Serpens is a constellation of the northern hemisphere. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy and it remains one of the 88 modern constellations defined by the International Astronomical Union....

, in its head (Serpens Caput). Alpha Serpentis has the proper names Unukalhai, from 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...

 عنق الحية ‘Unuq al-Ħayyah "the Serpent
Serpens
Serpens is a constellation of the northern hemisphere. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy and it remains one of the 88 modern constellations defined by the International Astronomical Union....

's Neck", and Cor Serpentis from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 "the Heart of the Serpent". It was a member of the indigenous Arabic 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,...

 al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines". It was a member of indigenous Arabic 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,...

 al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines"., along with δ Ser
Delta Serpentis
Delta Serpentis is a star system in the constellation Serpens, in its head . It was a member of indigenous Arabic asterism al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines"., along with α Ser , ε Ser , δ Oph , ε Oph , ζ Oph and γ Oph .According to the...

 (Qin, Tsin), ε Ser
Epsilon Serpentis
Epsilon Serpentis is a star in the constellation Serpens, in its head .It was a member of indigenous Arabic asterism al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines"., along with α Ser , δ Ser , δ Oph , ε Oph , ζ Oph and γ Oph .According to the...

 (Ba, Pa), δ Oph
Delta Ophiuchi
Delta Ophiuchi is a star in the constellation Ophiuchus. It has the traditional name Yed Prior ....

 (Yed Prior), ε Oph
Epsilon Ophiuchi
Epsilon Ophiuchi is a star in the constellation Ophiuchus. It has the traditional name Yed Posterior ....

 (Yed Posterior), ζ Oph
Zeta Ophiuchi
Zeta Ophiuchi is a star located in the constellation of Ophiuchus. It was a member of indigenous Arabic asterism al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines"., along with α Ser , δ Ser , ε Ser , δ Oph , ε Ser and γ Oph .According to the catalogue of stars...

 (Han) and γ Oph
Gamma Ophiuchi
Gamma Ophiuchi is a Class A4, fourth-magnitude star in the constellation Ophiuchus. Gamma Ophiuchi is a stellar system located about 95 light-years from Earth....

 (Tsung Ching).

According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, al-Nasaq al-Yamānī or Nasak Yamani were the title for two stars :δ Ser
Delta Serpentis
Delta Serpentis is a star system in the constellation Serpens, in its head . It was a member of indigenous Arabic asterism al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines"., along with α Ser , ε Ser , δ Oph , ε Oph , ζ Oph and γ Oph .According to the...

 as Nasak Yamani I and ε Ser
Epsilon Serpentis
Epsilon Serpentis is a star in the constellation Serpens, in its head .It was a member of indigenous Arabic asterism al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines"., along with α Ser , δ Ser , δ Oph , ε Oph , ζ Oph and γ Oph .According to the...

 as Nasak Yamani II (exclude this star, δ Oph
Delta Ophiuchi
Delta Ophiuchi is a star in the constellation Ophiuchus. It has the traditional name Yed Prior ....

, ε Oph
Epsilon Ophiuchi
Epsilon Ophiuchi is a star in the constellation Ophiuchus. It has the traditional name Yed Posterior ....

, ζ Oph
Zeta Ophiuchi
Zeta Ophiuchi is a star located in the constellation of Ophiuchus. It was a member of indigenous Arabic asterism al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines"., along with α Ser , δ Ser , ε Ser , δ Oph , ε Ser and γ Oph .According to the catalogue of stars...

 and γ Oph
Gamma Ophiuchi
Gamma Ophiuchi is a Class A4, fourth-magnitude star in the constellation Ophiuchus. Gamma Ophiuchi is a stellar system located about 95 light-years from Earth....

)

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 Right Wall of Heavenly Market Enclosure
Heavenly Market enclosure
Tian Shi Yuan, the Heavenly Market Enclosure , is one of the San Yuan or Three enclosures. Stars and constellations of this group are visible during late summer and early autumn in the Northern Hemisphere . The summer triangle lies directly to the northwest.-Asterisms:The asterisms are :...

, refers to an asterism which is represent eleven old states in China which is marking the right borderline of the enclosure, consisting of α Serpentis, β Herculis
Beta Herculis
Beta Herculis , which also has the name Kornephoros, is the brightest star in the constellation of Hercules. It has an apparent visual magnitude which varies between 2.76 and 2.81.Although β Herculis appears to the naked eye to be a single star, W. W...

, γ Herculis
Gamma Herculis
Gamma Herculis is a magnitude 3.74 binary star in the constellation Hercules. It is a giant star with a stellar classification of A9III that is located at a distance of about 195 light years from the Earth.-Name:...

, κ Herculis
Kappa Herculis
Kappa Herculis is a double star in the constellation Hercules. Traditional names that have been attributed to the star are "Marfik", "Marfak" or "Marsic", all of which come from the Arabic لمرفق Al-Mirfaq meaning "the elbow", a name it shares with Lambda Ophiuchi.- Properties :Kappa Herculis is a...

, γ Serpentis, β Serpentis
Beta Serpentis
Beta Serpentis is a star system in the constellation Serpens, in its head . It was a member of indigenous Arabic asterism al-Nasaq al-Sha'āmī, "the Northern Line" of al-Nasaqān "the Two Lines", along with β Her , γ Her and γ Ser .According to the catalogue of stars in the Technical Memorandum...

, δ Serpentis
Delta Serpentis
Delta Serpentis is a star system in the constellation Serpens, in its head . It was a member of indigenous Arabic asterism al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines"., along with α Ser , ε Ser , δ Oph , ε Oph , ζ Oph and γ Oph .According to the...

, ε Serpentis
Epsilon Serpentis
Epsilon Serpentis is a star in the constellation Serpens, in its head .It was a member of indigenous Arabic asterism al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines"., along with α Ser , δ Ser , δ Oph , ε Oph , ζ Oph and γ Oph .According to the...

, δ Ophiuchi
Delta Ophiuchi
Delta Ophiuchi is a star in the constellation Ophiuchus. It has the traditional name Yed Prior ....

, ε Ophiuchi
Epsilon Ophiuchi
Epsilon Ophiuchi is a star in the constellation Ophiuchus. It has the traditional name Yed Posterior ....

 and ζ Ophiuchi
Zeta Ophiuchi
Zeta Ophiuchi is a star located in the constellation of Ophiuchus. It was a member of indigenous Arabic asterism al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines"., along with α Ser , δ Ser , ε Ser , δ Oph , ε Ser and γ Oph .According to the catalogue of stars...

. Consequently, α Serpentis itself is known as , represent the state Shu
Shu (state)
The State of Shu was an ancient state in what is now Sichuan, China. It was conquered by Qin in 316 BC. Shu was based on the Chengdu Plain, in the western Sichuan basin with some extension northeast to the upper Han River valley. To the east was the Ba tribal confederation. Further east down the...

(蜀) (or Shuh)(together with λ Ser
Lambda Serpentis
Lambda Serpentis is a star in the constellation Serpens, in its head .- Hunt for substellar objects :...

 in R.H.Allen's works).

Properties

Alpha Serpentis is approximately 70 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...

 and is the brightest star in Serpens
Serpens
Serpens is a constellation of the northern hemisphere. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy and it remains one of the 88 modern constellations defined by the International Astronomical Union....

.

The primary star, Alpha Serpentis A is an orange K-type
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...

 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...

 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 +2.63. It has a total 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 70 times solar and a surface temperature of 4300 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. The radius of the star is some 15 times as large as that of the Sun. The magnitude +11.8 Alpha Serpentis B is 58 arcseconds from the primary, and the 13th magnitude Alpha Serpentis C lies 2.3 arcminutes from A.

External links

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