Star Constellation Facts: Pavo

Pavo Constellation Stars
Image Credit: Akira Fujii/David Malin

Pavo (“the peacock”) is one of 12 southern sky constellations devised by Petrus Plancius in the 16th century based upon the observations of Dutch explorers visiting the East Indies . Fortunately, it is neither as small or faint as many other southern constellations, making it a good jumping-off point for locating other constellations in the vicinity. The brightest star in Pavo, called Alpha Pavonis, is a blue-white subgiant found 179 light years from our solar system with an apparent visual magnitude of 1.94.

Location

Pavo is the 44th largest constellation, taking up an area of 378 square degrees of the southern celestial sphere. It can be seen by observers located between +30° and -90° of latitude, with the best time to look for the constellation being from August to October. Bordering Pavo is Indus to its east, Apus and Ara to its west, Telescopium to its north, and Octans to its south.

Johann Bayer Family

Pavo is a part of the Johann Bayer family of constellations, along with Apus, Chamaeleon, Dorado, Grus, Hydrus, Indus, Musca, Phoenix, Tucana and Volans.

History

Dutch astronomer Petrus Plancius invented 12 new southern sky constellations based upon the observations made by Dutch explorers Pieter Dirkszoon Keyser and Frederick de Houtman during their journey to the East Indies (Southeast Asia) in the 16th century. Plancius subsequently named many of his constellations after exotic animals, including Grus (“the Crane”), Tucana (“the toucan”), Phoenix, and Pavo (“the peacock”), with this particular group collectively known as the “Southern Birds”.

According to Greek legend, the goddess Hera, suspicious of her husband’s philandering ways with the nymph Io, ordered her servant, the hundred-eyed giant Argus Panoptes, to keep his watchful eyes upon her. After Zeus dispatched Hermes to slay the giant, Hera honored him by transformed his 100 eyes into the pattern on the tail of her sacred bird, the peacock.

Meteor Showers

There are two annual meteor showers associated with Pavo, namely the August Pavonids, which peaks around August 31st and is believed to be linked to Comet Levy (P/1991 L3).[54]; and the Delta Pavonids, which occur between 21st March and 8th April, with a peak on 5/6th April when up to 7 meteors per hour may be seen. This Southern Hemisphere only shower was discovered by Australian scientist Michael Buhagiar, and is linked to the Comet Grigg-Mellish.

Principal Stars

Pavo Constellation– Peacock (Alpha Pavonis), the constellation’s brightest star, is a blue-white subgiant (B2 IV) situated 179 light years from our solar system that shines with a visual magnitude of 1.94. It has around six times the Sun’s size and mass, with 2,200 times its luminosity. Alpha Pavonis is the main component in a spectroscopic binary system involving a 9th magnitude companion, with the pair having an orbital period of 11.753 days. There is also believed to be another two stars associated with the system.

– Beta Pavonis, the second brightest star in Pavo, is a white subgiant (A5IV) found 135 light years away of magnitude 3.42. This 60 million years old star is around 3.8 times bigger than the Sun, with 2.4 times its mass, and 58 times its luminosity. The equatorial rotation speed of Beta Pavonis is 81 km/s, giving it a rotation period of up to 2.3 days.

– Delta Pavonis, the constellation’s third brightest star, is a yellow subgiant (G8 IV) located a mere 19.92 light-years away that shines with a visual magnitude of 3.56. It is around 7 billion years old, and has roughly the same size, mass and luminosity as our sun. Together with a slow rotational velocity of just 1 km/s, and large quantities of iron in its atmosphere, indicative of a planet in its orbit, Delta Pavonis has been identified as an excellent star for further research by the SETI Institute (search for extraterrestrial intelligence).

Other stars of interest in the constellation includes the blue star Pi Pavonis; the blue-white giant Lambda Pavonis; the white dwarf Epsilon Pavonis; the yellow-white dwarf Gamma Pavonis; the orange giant Eta Pavonis and Xi Pavonis; and the Cepheid variable star Kappa Pavonis, whose magnitude varies from 3.8 to 5.2 over a 9.0908 day period.

Notable Deep-Sky Objects

Pavo is located in a rather starless area of the night sky, and contains no Messier objects, and only a few notable deep sky targets for stargazers.

NGC 6752– NGC 6752 is a globular cluster situated 13,000 light-years distant with a visual magnitude of 5.4, making it the third brightest example of its kind in the night sky, behind 47 Tucanae (NGC 104) in the constellation Tucana, and Omega Centauri (NGC 5139) in Centaurus. It is around 11.78 billion years old, meaning it is also one of the oldest globular clusters in the Milky Way, and contains hundreds of thousand stars, 38% of which near its core are binary systems. Collisions between its stars have also resulted in a prevalence of blue stragglers.

– IC 4686, IC 4689 and IC 4687 are a triplet of interacting galaxies found around 250 million light-years away which in the distant future will ultimately merge into one huge galaxy. In the meantime, their interactions have resulted in starburst regions in which millions of young blue stars are being created at a faster rate than usually observed.

NGC 6872– NGC 6872 is a spiral galaxy situated around 210 million light-years from our solar system that at 522,000 light-years in diameter is one of the largest spiral galaxies yet discovered. It is about five billion years old, and has two elongated arms, the extended portions of which contains many young blue stars. The galaxy’s out stretched shape is caused by an ongoing gravitational interaction with the nearby lenticular galaxy IC 4970, which is about 212 million light-years from Earth.

Other objects of interest in Pavo includes the barred spiral galaxy NGC 6782, the intermediate spiral galaxy NGC 6744, and the dwarf galaxy IC 4662.

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