Alpha Pavonis is the brightest star in Pavo, the Peacock, a southern constellation invented by Dutch explorers around the year 1600. The star shines at magnitude 1.94, and is one of the brighter stars in the sky, but is not visible north of 32° north latitude.
Alpha Pavonis is also known by the name Peacock. This name was assigned by Her Majesty's Nautical Almanac Office in the late 1930s during the creation of The Air Almanac, a navigational almanac for the Royal Air Force. Of the 57 stars included in the new almanac, two had no classical names: ε Car and α Pav. The RAF insisted that all stars have names, so new names were invented. Alpha Pavonis was named Peacock, for obvious reasons, while ε Car was called Avior.
Properties
Peacock is a hot blue class B2 IV subgiant with a temperature of 18,700 K. From its distance of 180 light years, it has a visual luminosity of 450 suns; however, when ultraviolet light is taken into account, the total luminosity climbs to 2100 suns. This implies a radius 4.4 times solar. Direct measure of the star's angular size gives very nearly the same dimension. With a mass somewhere around 5 to 6 times that of the Sun, the star will eventually become a massive white dwarf.
Peacock has also been found to be a close spectroscopic binary star, with a short period of only 11.8 days, implying a separation of only 0.21 AU. The orbit is nearly in the plane of the sky, with an orbital tilt of only a few degrees. That conclusion is consistent with a low rotation speed of only 39 km/sec. The star must be spinning with its rotational axis directed nearly at us.
[Adapted from STARS by Jim Kaler, Professor Emeritus of Astronomy, University of Illinois]