Aquarius

Aquarius is a constellation of the zodiac, situated between Capricornus and Pisces. Its name is Latin for "water-carrier" or "cup-carrier", and its symbol is ♒, a representation of water. Aquarius is one of the oldest of the recognized constellations along the zodiac (the sun's apparent path). It was one of the 48 constellations listed by the 2nd century AD astronomer Ptolemy, and it remains one of the 88 modern constellations. It is found in a region often called the Sea due to its profusion of constellations with watery associations such as Cetus the whale, Pisces the fish, and Eridanus the river. ... In the first century CE, Ptolemy's Almagest established the common Western depiction of Aquarius. His water jar, an asterism itself, consists of Gamma, Pi, Eta, and Zeta Aquarii; it pours water in a stream of more than 20 stars terminating with Fomalhaut, now assigned solely to Piscis Austrinus. The water bearer's head is represented by 5th magnitude 25 Aquarii while his left shoulder is Beta Aquarii; his right shoulder and forearm are represented by Alpha and Gamma Aquarii respectively. ... Despite both its prominent position on the zodiac and its large size, Aquarius has no particularly bright stars, with its 4 brightest stars less than magnitude 2. However, recent research has shown that there are several stars lying within its borders that possess planetary systems. ... α Aquarii, also known as Sadalmelik, is a G2 spectral class star (yellow supergiant) named in Arabic for the phrase "the lucky stars of the king". It is the second brightest star in Aquarius with a magnitude of 2.96 (though it has an absolute magnitude of -4.5) and is 523 light-years from Earth. It has a luminosity of 5250 L☉. ... β Aquarii, sometimes called Sadalsuud, is a G0 spectral class star (yellow supergiant) named for the Arabic phrase meaning "luckiest of the lucky stars". It is the brightest star in Aquarius with an apparent magnitude of 2.91 and an absolute magnitude of -4.5. Sadalsuud is 537 light-years from Earth and has a luminosity of 5250 L☉, the same as α Aquarii. ... δ Aquarii, also known as Scheat or Skat, is a blue-white A2 spectral class star of magnitude 3.27 and luminosity of 105 L☉. ... ζ Aquarii is an F2 spectral class double star; both stars are white. Overall, it appears to be of magnitude 3.6 and luminosity of 50 L☉. The primary has a magnitude of 4.53 and the secondary a magnitude of 4.31, but both have an absolute magnitude of 0.6. Its orbital period is 760 years; the two components are currently moving farther apart. ... Twelve exoplanet systems have been found in Aquarius as of 2013. Gliese 876, one of the nearest stars to Earth at a distance of 15 light-years, was the first red dwarf star to be found to possess a planetary system. It is orbited by four planets, including one terrestrial planet 6.6 times the mass of Earth. The planets vary in orbital period from 2 days to 124 days. 91 Aquarii is an orange giant star orbited by one planet, 91 Aquarii b. The planet's mass is 2.9 times the mass of Jupiter, and its orbital period is 182 days. Gliese 849 is a red dwarf star orbited by the first known long-period Jupiter-like planet, Gliese 849 b. The planet's mass is 0.99 times that of Jupiter and its orbital period is 1,852 days. ... Because of its position away from the galactic plane, the majority of deep-sky objects in Aquarius are galaxies, globular clusters, and planetary nebulae. Aquarius contains three deep sky objects that are in the Messier catalog: the globular clusters Messier 2, Messier 72, and the open cluster Messier 73. Two well-known planetary nebulae are also located in Aquarius: the Saturn Nebula (NGC 7009), to the eastwest of μ Aquarii; and the famous Helix Nebula (NGC 7293), southwest of δ Aquarii. ... There are three major meteor showers with radiants in Aquarius: the Eta Aquariids, the Delta Aquariids, and the Iota Aquariids. [Aquarius (constellation). Wikipedia]