Sagittarius constellation lies in the southern sky. It is one of the constellations of the zodiac. It represents the archer.
Sagittarius is usually depicted as a centaur holding a bow and arrow. The constellation’s symbol is . It is also associated with Crotus, the satyr who kept company of the Muses on Mount Helicon. Sagittarius is one of the largest southern constellations. It is easy to find because it lies on the Milky Way and its brightest stars form an asterism known as the Teapot. Like other zodiac constellations, Sagittarius was first catalogued by the Greek astronomer Ptolemy in the 2nd century.
The constellation contains the Arches Cluster, the Quintuplet Cluster with the luminous Pistol Star, the Galactic centre, the radio source Sagittarius A, and a number of very famous deep sky objects, including the Sagittarius Dwarf Elliptical Galaxy, the Sagittarius Dwarf Irregular Galaxy, Barnard’s Galaxy, the Bubble Nebula, and as many as 15 Messier objects, among them the Sagittarius Star Cloud (Messier 24), the Omega Nebula (Messier 17), Messier 18, the Lagoon Nebula (Messier 8), and the Trifid Nebula (Messier 20).
FACTS, LOCATION & MAP
Sagittarius is the 15th largest constellation in the sky. It occupies an area of 867 square degrees. It is located in the fourth quadrant of the southern hemisphere (SQ4) and can be seen at latitudes between +55° and -90°. The neighboring constellations are Aquila, Capricornus, Corona Australis, Indus, Microscopium, Ophiuchus, Scutum, Scorpius, Serpens Cauda and Telescopium.
Sagittarius has seven stars brighter than magnitude 3.00 and three stars located within 10 parsecs (32.6 light years) of Earth. The brightest star in Sagittarius is Kaus Australis, Epsilon Sagittarii (spectral class B9.5 III), with an apparent magnitude of 1.79. The nearest star is Ross 154 (V1216 Sagittarii, spectral class M3.5V), located at a distance of only 9.69 light years from Earth.
The constellation has 32 stars with confirmed planets. OGLE-2006-BLG-109L (spectral class M0V) has two known exoplanets, suspected analogs of Jupiter and Saturn, discovered in 2008. The planets SWEEPS-04, orbiting the magnitude 18 star SWEEPS J175853.92−291120.6 (F5V), and SWEEPS-11, with the parent star SWEEPS J175902.67−291153.5, are among the most distant exoplanets known, both located at a distance of 27,710 light years from Earth. The star HD 169830 (F9V) is orbited by two Jupiter-like planets, discovered in 2000 and 2013. HD 190647 (G5IV) has a known exoplanet, discovered in 2007. A transiting planet was spotted orbiting the magnitude 16 eclipsing variable star OGLE-TR-10 (G2V) in 2002. The red dwarf MOA-2009-BLG-387L, located almost 20,000 light years away, is host to an orbiting planet with a mass between 1.0 and 6.7 times that of Jupiter. A gas giant planet was discovered orbiting the orange dwarf HD 164604 (K3.5Vk) in 2010.
Other stars with confirmed exoplanets include HD 171238 (G8 V), HD 179949 (F8 V), HD 181720 (G1V), HD 187085 (G0V), WASP-67 (K0V), MOA-2011-BLG-293L (M1.5V), MOA-2009-BLG-319L (K8V), HD 181342 (K0III), HD 180902 (K0III/IV), OGLE-TR-56 (G), OGLE-2003-BLG-235L (K5), OGLE-2005-BLG-169L (M), MOA-2007-BLG-192L, and MOA-2007-BLG-400L (M3V).
Sagittarius belongs to the Zodiac family of constellations, along with Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, Capricornus, Aquarius and Pisces.
Sagittarius contains 15 Messier objects: Messier 8 (M8, NGC 6523, Lagoon Nebula), Messier 17 (M17, NGC 6618 Omega, Swan, Horseshoe or Lobster Nebula), Messier 18 (M18, NGC 6613), Messier 20 (M20, NGC 6514, Trifid Nebula), Messier 21 (M21, NGC 6531), Messier 22 (M22, NGC 6656, Sagittarius Cluster), Messier 23 (M23, NGC 6494), Messier 24 (M24, NGC 6603, Sagittarius Star Cloud), Messier 25 (M25, IC 4725), Messier 28 (M28, NGC 6626), Messier 54 (M54, NGC 6715), Messier 55 (M55, NGC 6809), Messier 69 (M69, NGC 6637), Messier 70 (M70, NGC 6681) and Messier 75 (M75, NGC 6864).
There are no meteor showers associated with the constellation.
MYTHOLOGY
In Greek mythology, Sagittarius represents a centaur, a half human, half horse creature with the torso of a man and the body and four legs of a horse. The centaur is depicted as aiming an arrow toward the heart of the neighbouring constellation Scorpio, represented by the red supergiant star Antares. Sometimes Sagittarius is wrongly identified as the centaur Chiron, represented by the constellation Centaurus.
Sagittarius constellation has its roots in Sumerian mythology. Eratosthenes associated it with Crotus, a mythical creature with two feet and a satyr’s tail, who was the nurse to the nine Muses, daughters of Zeus.
Eratosthenes argued that the constellation really represented a satyr and not a centaur. According to the Roman author Hyginus, Crotus was the son of Pan and the archer the constellation was named after. Crotus invented archery and lived on Mount Helicon. Because he was close to the Muses, they were the ones who asked Zeus to place him in the sky.
In Babylonian mythology, Sagittarius is associated with the centaur-like god Nergal, and depicted with two heads – one human and one panther – and also wings, and the stinger of a scorpion positioned above a horse’s tail.
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