La Memoria - 15 "Altair"

Altair is located 16.7 light-years (5.13 parsecs) from Earth and is one of the closest stars visible to the naked eye. Along with Beta Aquilae and Gamma Aquilae, it forms the well-known line of stars sometimes referred to as the Family of Aquila or Shaft of Aquila.

Altair is a type-A main sequence star with approximately 1.8 times the mass of the Sun and 11 times its luminosity. Altair possesses an extremely rapid rate of rotation; it has a rotational period of approximately 9 hours. For comparison, the equator of the Sun requires a little more than 25 days for a complete rotation. This rapid rotation forces Altair to be oblate; its equatorial diameter is over 20 percent greater than its polar diameter.

Satellite measurements made in 1999 with the Wide Field Infrared Explorer showed that the brightness of Altair fluctuates slightly, varying by less than a thousandth of a magnitude. As a result, it was identified in 2005 as a Delta Scuti variable star. Its light curve can be approximated by adding together a number of sine waves, with periods that range between 0.8 and 1.5 hours.
The name Altair has been used since medieval times. It is an abbreviation of the Arabic phrase النسر الطائر, an-nasr aṭ-ṭā’ir (English: The flying eagle). The term Al Nesr Al Tair appeared in Al Achsasi Al Mouakket catalogue, which was translated into Latin as Vultur Volans. This name was applied by the Arabs to the asterism of α, β, and γ Aquilae and probably goes back to the ancient Babylonians and Sumerians, who called α Aquilae the eagle star. The spelling Atair has also been used. Medieval astrolabes of England and Western Europe depicted Altair and Vega as birds.

The Koori people of Victoria also knew Altair as Bunjil, the Wedge-tailed Eagle, and β and γ Aquilae are his two wives the Black Swans. The people of the Murray River knew the star as Totyerguil. The Murray River was formed when Totyerguil the hunter speared Otjout, a giant Murray Cod, who, when wounded, churned a channel across southern Australia before entering the sky as the constellation Delphinus.

In Chinese, the asterism consisting of α, β, and γ Aquilae is known as hegu (河鼓; lit. "river drum").[23] Altair is thus known as hegu er (河鼓二; lit. "river drum two", meaning the "second star of the drum at the river").

However, Altair is better known by its other names: qianniu xing (牵牛星) or niulang xing (牛郎星), translated as the cowherd star.[28][29] These names are an allusion to a love story, The Weaver Girl and the Cowherd, in which Niulang (represented by Altair) and his two children (represented by β and γ Aquilae) are separated from respectively their wife and mother Zhinu (represented by Vega) by the Milky Way. They are only permitted to meet once a year, when magpies form a bridge to allow them to cross the Milky Way.

The people of Micronesia called Altair as Mai-lapa, "big/old breadfruit", while the Māori people called this star as Poutu-te-rangi, "pillar of heaven".

>> Altair adalah salah satu bintang yang memiliki banyak nama dan legenda, terkenal sering di pasangkan dengan Vega. Dalam bahasa Arab, Altair sendiri berarti elang yang sedang terbang. Orang-orang Babilonia menyebutnya bintang elang adapun orang Mauri menyebut bintang ini 'pillar of heaven' atau pilar surga.

Source : http://en.wikipedia.org/wiki/Altair

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L.N

Sept 1st, 2014