Sagittarius is a
constellationIn 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....
of the
zodiacIn astronomy, the zodiac is a circle of twelve 30° divisions of celestial longitude which are centred upon the ecliptic: the apparent path of the Sun across the celestial sphere over the course of the year...
, the one containing the galactic center. Its name is
LatinLatin 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...
for the
archerArchery is the art, practice, or skill of propelling arrows with the use of a bow, from Latin arcus. Archery has historically been used for hunting and combat; in modern times, however, its main use is that of a recreational activity...
, and its symbol is
(
UnicodeUnicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...
U+2650 ♐), a stylized arrow. Sagittarius is commonly represented as a
centaurIn Greek mythology, a centaur or hippocentaur is a member of a composite race of creatures, part human and part horse...
drawing a bow. It lies between
OphiuchusOphiuchus is a large constellation located around the celestial equator. Its name is from the Greek "serpent-bearer", and it is commonly represented as a man grasping the snake that is represented by the constellation Serpens. Ophiuchus was one of the 48 constellations listed by the 2nd-century...
to the west and
CapricornusCapricornus is one of the constellations of the zodiac; it is often called Capricorn, especially when referring to the corresponding astrological sign. Its name is Latin for "horned male goat" or "goat horn", and it is commonly represented in the form of a sea-goat: a mythical creature that is half...
to the east.
Visualizations
The constellation's brighter stars (from left to right on the map: τ, ζ, σ, φ, λ, ε, δ, and γ
2 Sagittarii) form an easily recognizable
asterismIn 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,...
known as 'the
TeapotA teapot is a vessel used for steeping tea leaves or a herbal mix in near-boiling water. Tea may be either in a tea bag or loose, in which case a tea strainer will be needed, either to hold the leaves as they steep or to catch the leaves inside the teapot when the tea is poured...
'. The stars
δ SgrDelta Sagittarii is a star system in the constellation Sagittarius. It has the traditional names Kaus Media, Kaus Meridionalis, and Media. Kaus Media is 306 light years from Earth and radiates with a total luminosity of 1180 times that of the Sun...
(Kaus Media),
ε SgrEpsilon Sagittarii is a binary star that lies 144.64 light-years distant in the constellation Sagittarius. It has a faint, 14th magnitude, companion, Epsilon Sagittarii B, 32 arcseconds distant....
(Kaus Australis),
ζ SgrZeta Sagittarii is the third brightest star system in the constellation Sagittarius. It has the traditional name Ascella from a Late Latin word meaning armpit....
(Ascella), and
φ SgrPhi Sagittarii is a star in the constellation Sagittarius. It is a member of the teapot asterism marking the junction of lid and handle.Phi Sagittarii is a spectral type B8 giant and has an apparent magnitude of +3.17...
form the body of the pot;
λ SgrLambda Sagittarii is a star within the constellation Sagittarius. The star marks the top of the Archer's bow, whence its traditional name Kaus Borealis. It also marks the top of the lid of the so-called "Teapot" asterism...
(Kaus Borealis) is the point of the lid;
γ2 SgrGamma Sagittarii is a 3rd-magnitude star in the constellation Sagittarius.It was temporarily referred to Gamma-2 Sagittarii . The Bayer designation "Gamma Sagittarii" was temporarily shared by two star systems in this constellation, γ1 Sagittarii and γ2 Sagittarii...
(Alnasl) is the tip of the spout; and
σ SgrSigma Sagittarii is the second brightest star system in the constellation Sagittarius.Its modern name Nunki is an Assyrian or Babylonian name recovered by archaeologists and made public by R.H.Allen....
(Nunki) and
τ SgrTau Sagittarii is a star in the constellation Sagittarius, 120 light years from Earth. In ancient Chinese astronomy, it is the 5th star of 6 stars in the Dipper or 'South Dipper' mansion of the Black Tortoise of the North...
the handle.
The constellation as a whole is often depicted as having the rough appearance of a stick-figure archer drawing its bow, with the fainter stars providing its horse body.
Stars
α SgrAlpha Sagittarii is a star in the Sagittarius constellation. It has the traditional names 天淵三 , Alrami and Rukbat, derived from the Arabic rukbat al-rāmī = the knee of the archer...
(Rukbat) is not the brightest star of the constellation, having a magnitude of only 3.96 (not shown on the main map as it is located below the map's southeastern corner, north is up).
With 22 stars in this constellation known to have planets, Sagittarius has more known planetary host stars than any other constellation.
Deep-sky objects
The
Milky WayThe Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
is at its densest near Sagittarius, as this is where the
galactic centerThe Galactic Center is the rotational center of the Milky Way galaxy. It is located at a distance of 8.33±0.35 kpc from the Earth in the direction of the constellations Sagittarius, Ophiuchus, and Scorpius where the Milky Way appears brightest...
lies. Consequently, Sagittarius contains many star clusters and nebulae. One of the brightest of the star clusters is
Messier 55Messier 55 is a globular cluster in the constellation Sagittarius. It was discovered by Nicolas Louis de Lacaille in 1751 and catalogued by Charles Messier in 1778. M55 is at a distance of about 17,300 light-years away from Earth. Only about half a dozen variable stars have been discovered in...
, about 7.5° west of δ Sgr.
The constellation contains nebulae such as the
Lagoon NebulaThe Lagoon Nebula is a giant interstellar cloud in the constellation Sagittarius. It is classified as an emission nebula and as an H II region....
(Messier 8), near λ Sagittarii, the
Omega NebulaThe Omega Nebula, also known as the Swan Nebula, Checkmark Nebula, Lobster Nebula, and the Horseshoe Nebula is an H II region in the constellation Sagittarius. It was discovered by Philippe Loys de Chéseaux in 1745. Charles Messier catalogued it in 1764...
(Messier 17), also known as the Swan or Horseshoe Nebula, near the border with
ScutumScutum is a small constellation introduced in the seventeenth century. Its name is Latin for shield.-History:Scutum is the only constellation that owes its name to a non-classical historical figure...
; and the
Trifid NebulaThe Trifid Nebula is an H II region located in Sagittarius. Its name means 'divided into three lobes'...
(Messier 20), a large nebula containing some very young, hot stars. The grouping of Lagoon Nebula, Trifid Nebula, and NGC 6559 is often called the
Sagittarius triplet.
In 1999 a violent outburst at V4641 Sgr was thought to have revealed the location of the closest known black hole to Earth, but later investigation increased its estimated distance by a factor of 15. The complex radio source
Sagittarius ASagittarius A is a complex radio source at the center of our galaxy, the Milky Way. It is located in the sky in the Sagittarius constellation...
is also here. Astronomers believe that one of its components, known as Sagittarius A*, is associated with a
supermassive black holeA supermassive black hole is the largest type of black hole in a galaxy, in the order of hundreds of thousands to billions of solar masses. Most, and possibly all galaxies, including the Milky Way, are believed to contain supermassive black holes at their centers.Supermassive black holes have...
at the
center of the galaxyThe Galactic Center is the rotational center of the Milky Way galaxy. It is located at a distance of 8.33±0.35 kpc from the Earth in the direction of the constellations Sagittarius, Ophiuchus, and Scorpius where the Milky Way appears brightest...
. The
Sagittarius Dwarf Elliptical GalaxyThe Sagittarius Dwarf Elliptical Galaxy is an elliptical loop-shaped satellite galaxy of the Milky Way Galaxy. It consists of four globular clusters, the main cluster being discovered in 1994...
is located just outside the
Milky WayThe Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
.
Mythology
The Babylonians identified Sagittarius as the god Nerigal or Nergal, a strange centaur-like creature firing an arrow from a bow. It is generally depicted with wings, with two heads, one panther head and one human head, as well as a scorpion's stinger raised above its more conventional horse's tail. The Sumerian name Pabilsag is composed of two elements - Pabil, meaning 'elder paternal kinsman' and Sag, meaning 'chief, head'. The name may thus be translated as the 'Forefather' or 'Chief Ancestor'. The figure is reminiscent of modern depictions of Sagittarius.
In
Greek mythologyGreek mythology is the body of myths and legends belonging to the ancient Greeks, concerning their gods and heroes, the nature of the world, and the origins and significance of their own cult and ritual practices. They were a part of religion in ancient Greece...
, Sagittarius is identified as a
centaurIn Greek mythology, a centaur or hippocentaur is a member of a composite race of creatures, part human and part horse...
: half human, half horse. In some legends, the Centaur
ChironIn Greek mythology, Chiron was held to be the superlative centaur among his brethren.-History:Like the satyrs, centaurs were notorious for being wild and lusty, overly indulgent drinkers and carousers, given to violence when intoxicated, and generally uncultured delinquents...
was the son of Philyra and
SaturnSaturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus , the Babylonian Ninurta and the Hindu Shani. Saturn's astronomical symbol represents the Roman god's sickle.Saturn,...
, who was said to have changed himself into a horse to escape his jealous wife,
RheaRhea was the Titaness daughter of Uranus, the sky, and Gaia, the earth, in Greek mythology. She was known as "the mother of gods". In earlier traditions, she was strongly associated with Gaia and Cybele, the Great Goddess, and was later seen by the classical Greeks as the mother of the Olympian...
. Chiron was eventually immortalised in the constellation of Centaurus or in some version, Sagittarius.
The arrow of this constellation points towards the star
AntaresAntares is a red supergiant star in the Milky Way galaxy and the sixteenth brightest star in the nighttime sky . Along with Aldebaran, Spica, and Regulus it is one of the four brightest stars near the ecliptic...
, the "heart of the scorpion."
Astrology
, the Sun appears in the constellation Sagittarius from December 18 to January 18. In tropical astrology, the Sun is considered to be in the sign Sagittarius from November 22 to December 21, and in
sidereal astrologySidereal and tropical are astronomical terms used to describe two different definitions of a "year". They are also used as terms for two systems of ecliptic coordinates used in astrology....
, from December 16 to January 14.
External links