Scorpius

---

Scorpius is a constellation in the southern hemisphere, located near the centre of the Milky Way galaxy. It was one of the constellations introduced by the Greek astronomer Ptolemy in the 2nd century. Scorpius represents the scorpion that stung and killed Orion, the mythical hunter who boasted that he could kill any wild animal. The Earth sent the scorpion to kill Orion after hearing what he had said. In another version of the Greek tale, it was the goddess Artemis who sent the scorpion after Orion had tried to ravish her. Even today, it is said that Orion flees under the horizon whenever Scorpius rises in the sky. The two constellations are placed opposite each other. The Sumerians also identified the constellation with the scorpion, or Gir-tab. Scorpius is depicted with its tail and sting poised in the air, ready to strike.

The constellation Scorpius occupies an area of 497 square degrees and contains ten stars with known planets. It can be seen at latitudes between +40° and -90° and is best visible at 9 p.m. during the month of July. Astronomically, the Sun lingers in Scorpius only for a week, from November 23 to November 30, but most astrologers consider it to be in the sign of Scorpio from October 23 to November 23. In sidereal astrology, the Sun passes through Scorpio from November 16 to December 16.

Scorpius contains a number of bright stars, most of which are members of the Scorpius-Centaurus Association, the closest stellar association to our solar system.

The brightest star in the constellation is [7516] alpha Scorpii, or Antares ("like Mars"), named for its reddish-orange colour, which resembles that of the planet Mars. Antares is a red supergiant with a radius about 800 times that of the Sun. It is classified as a variable star; its apparent magnitude varies between 0.9 and 1.8. It has a hot blue companion star about 2.9 arcseconds away.

Antares is the 16th brightest star in the sky. It is approximately 600 light-years distant from Earth. It is also of the brightest stars near the ecliptic, the Sun’s apparent path in the sky. The only other first magnitude stars on the ecliptic are [7931] Aldebaran (alpha Tauri), [8774] Spica (alpha Virginis) and [4806] Regulus (alpha Leonis).

Antares is significant in many different cultures. In Arab tradition, it was said to be the star of the warrior poet Antarah ibn Shaddad. Arabs also used to call the star Kalb al Akrab ("the scorpion's hart"), a translation of the ancient Greek name for the star, Kardia Scorpiou, as well as the Latin, Cor Scorpii.

In Egyptian tradition, the light of Antares played an important part in the ceremonies performed in the temples. Ancient Persians called the star Satevis and considered it to be one of the four "royal stars." Antares was also important in the religion of Stregheria, a pagan, pre-Christian religion in Italy in which the star was believed to be a fallen angel and guardian of the western gate. In ancient India, Antares was known as Jyeshtha.

[7517] lambda Scorpii, the second brightest star in Scorpius, is also called Shaula ("the sting"). It is located at the end of the scorpion’s tail, marking the sting. Shaula is a multiple star, composed of a B-type subgiant, which is itself a triple star, and two fainter companions. The primary star is classified as a Beta Cephei variable, a star that shows changes in luminosity because of pulsations on its surface. Shaula is approximately 700 light-years distant.

[7522]-[7553] beta Scorpii, also known as Graffias ("claws") and Acrab ("scorpion"), is another multiple star system. The Chinese called it the Fourth Star of the Room. Acrab appears as a binary star composed of two hot, B-class stars that are suspected spectroscopic binaries themselves.

[7520] delta Scorpii, or Dschubba ("forehead") marks the middle of the scorpion’s head. It is also known as Dzuba, Iclarcrau and Iclarkrav. It is a multiple star with a hot class B star for the primary component. It lies about 402 light-years from Earth.

[7518] theta Scorpii is a yellow giant star approximately 270 light-years distant, whose luminosity is 960 times that of the Sun. It is also known by its Sumerian names Girtab ("the scorpion") and Sargas, whose meaning has been lost.

[7535] nu Scorpii or Jabbah ("forehead") has at least four components, split into two groups. The brighter pair consists of B class subgiants and the fainter pair is composed of B class main sequence dwarfs. The star system lies approximately 437 light-years from Earth. It is the light of nu Scorpii that illuminates the large reflection nebula IC 4592, also located in Scorpius.

[7545] xi Scorpii has at least five components, split into two groups lying 4.67 arcminutes away from each other. The brighter group contains two yellow-white F-type stars – a subgiant and a dwarf – and a fainter companion. The fainter group consists of two K-type stars.

[7525] pi Scorpii, another multiple star system, is composed of a contact binary star of the Beta Lyrae type and a fainter, more distant companion. Both components of the contact binary are hot blue-white dwarfs. Pi Scorpii is approximately 459 light-years distant.

[7528] mu-1 Scorpii is another example of an eclipsing binary star of the Beta Lyrae type. Both components are blue-white stars; one is a subgiant and the other a dwarf. The system is about 822 light-years away from Earth.

[7526] sigma Scorpii is also known as Al Niyat ("the arteries"), a name it shares with [7524] tau Scorpii. It is another multiple star, 735 light-years distant. Its primary component is a blue-white giant classified as a Beta Cephei variable. [7524] tau Scorpii is a blue-white dwarf, approximately 430 light-years distant.

[7523] upsilon Scorpii, or Lesath ("bite of a poisonous animal"), is another hot B-class star, a subgiant, in the constellation. It is approximately 520 light-years distant and has luminosity 12,300 times that of the Sun.

Scorpius also contains several notable deep sky objects. The Butterfly Cluster, or Messier 6 (NGC 6405) is an open cluster of stars that form a shape similar to that of a butterfly. The brightest star in the cluster is BM Scorpii, an orange supergiant, while most of the other bright members are hot, blue B-type stars.

The Ptolemy Cluster, named after the Greek astronomer, is also known as Messier 7 or NGC 6475. It is an open cluster visible to the naked eye, located near the scorpion's sting. It contains about 80 stars.

Messier 4 (NGC 6121) is a globular cluster easily found and observed even in very small telescopes. It lies 1.3 degrees away from [7516] Antares. The cluster is approximately 7,200 light-years distant. It is one of the closest globular clusters to Earth.

Messier 80 (NGC 6093) is another globular cluster in Scorpius. It can be found halfway between [7516] alpha and [7522]-[7553] beta Scorpii. It is one of the densest globular clusters in the Milky Way, containing several hundred thousand stars. Messier 80 lies 32,600 light-years from Earth.

NGC 6231 is an open cluster that can be seen near zeta Scorpii. [7544] zeta-1 Scorpii (HR 6262) belongs to the cluster and is the hottest star in it. NGC 6231 is believed to be only 3.2 million years old. It belongs to the Scorpius OB Association of very young stars. The cluster is approaching us at the speed of 22 kilometres per second.

Scorpius belongs to the Zodiac family of constellations, along with Leo, Virgo, Libra, Sagittarius, Capricornus, Aquarius, Pisces, Aries, Taurus, Gemini and Cancer.

Constellations directly bordering Scorpius are Sagittarius, Ophiuchus, Libra, Lupus, Norma, Ara and Corona Australis.