Pavo

Pavo is a constellation in the southern sky with the Latin name for peacock. It is one of twelve constellations conceived by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman. Pavo first appeared on a 35-cm (14 in) diameter celestial globe published in 1598 in Amsterdam by Plancius and Jodocus Hondius and was depicted in Johann Bayer's star atlas Uranometria of 1603. French explorer and astronomer Nicolas Louis de Lacaille gave its stars Bayer designations in 1756. The constellations Pavo, Grus, Phoenix and Tucana are collectively known as the "Southern Birds". The constellation's brightest member, Alpha Pavonis, is also known as Peacock and appears as a 1.91-magnitude blue-white star, but is actually a spectroscopic binary. Delta Pavonis is a nearby Sun-like star some 19.9 light years distant. Six of the star systems in Pavo have been found to host planets, including HD 181433 with a super-earth, and HD 172555 with evidence of a major interplanetary collision in the past few thousand years. The constellation contains NGC 6752, the third-brightest globular cluster in the sky, and the spiral galaxy NGC 6744, which closely resembles our Milky Way but is twice as large. Pavo is the radiant of two annual meteor showers: the Delta Pavonids and August Pavonids. ... Pavo is bordered by Telescopium to the north, Apus and Ara to the west, Octans to the south, and Indus to the east and northeast. ... Lying near the constellation's northern border with Telescopium is Alpha Pavonis, the brightest star in Pavo. Its proper name — Peacock — is an English translation of the constellation's name. ... Alpha has an apparent (or visual) magnitude of 1.91 and spectral type B2IV. It is a spectroscopic binary system, one estimate placing the distance between the pair of stars as 0.21 astronomical units (AU), or half the distance between Mercury and the Sun. The two stars rotate around each other in a mere 11 days and 18 hours. The star system is located around 180 light years away from Earth. With an apparent magnitude of 3.43, Beta Pavonis is the second-brightest star in the constellation. A white giant of spectral class A7III, it is an aging star that has used up the hydrogen fuel at its core and has expanded and cooled after moving off the main sequence. It lies 135 light years away from our solar system. Lying a few degrees west of Beta is Delta Pavonis, a nearby Sun-like but more evolved star; this is a yellow subgiant of spectral type G8IV and apparent magnitude 3.56 that is only 19.9 light years distant from Earth. ... Located in the west of the constellation and depicting the peacock's tail are Eta and Xi Pavonis. At apparent magnitude 3.6, Eta is a luminous orange giant of spectral type K2II some 350 light years distant from Earth. ... Planetary systems and debris disks. Six stars with planetary systems have been found. Three planets have been discovered in the system of the orange star HD 181433, an inner super-earth with an orbital period of 9.4 days and two outer gas giants with periods of 2.6 and 6 years respectively. HD 196050 and HD 175167 are yellow G-class Sun-like stars, while HD 190984 is an F-class main sequence star slightly larger and hotter than the Sun; all three are accompanied by a gas giant companion. HD 172555 is a young white A-type main sequence star, two planets of which appear to have had a major collision in the past few thousand years. Spectrographic evidence of large amounts of silicon dioxide gas indicates the smaller of the two, which had been at least the size of Earth's moon, was destroyed, and the larger, which was at least the size of Mercury, was severely damaged. Evidence of the collision was detected by NASA's Spitzer Space Telescope. In the south of the constellation, Epsilon Pavonis is a 3.95-magnitude white main sequence star of spectral type A0Va located around 105 light years distant from Earth. It appears to be surrounded by a narrow ring of dust at a distance of 107 AU. ... Deep-sky objects. The globular cluster NGC 6752 contains an estimated 100,000 stars. The deep-sky objects in Pavo include NGC 6752, the third-brightest globular cluster in the sky, after 47 Tucanae and Omega Centauri. An estimated 100 light years across, it is thought to contain 100,000 stars. Lying three degrees to the south is NGC 6744, a spiral galaxy around 30 million light years away from Earth that resembles the Milky Way, but is twice its diameter. A type 1c supernova was discovered in the galaxy in 2005; known as SN2005at, it peaked at magnitude 16.8. The dwarf galaxy IC 4662 lies 10 arcminutes northeast of Eta Pavonis, and is of magnitude 11.62. Located only 8 million light years away, it has several regions of high star formation. The 14th-magnitude galaxy IC 4965 lies 1.7 degrees west of Alpha Pavonis, and is a central member of the Shapley Supercluster. ... Meteor showers. Pavo is the radiant of two annual meteor showers: the Delta Pavonids and August Pavonids. [Pavo (constellation). Wikipedia]