Altair
Channel: all the knowledge of the universe PRINCIPIA
Date: 2021-12-05

Altair, by Wikipedia https://en.wikipedia.org/wiki?curid=3078 / CC BY SA 3.0

#Aquila_(constellation)
#A-type_main-sequence_stars
#Multiple_stars
#Flamsteed_objects
#Bayer_objects
#Henry_Draper_Catalogue_objects
#Hipparcos_objects
#HR_objects
#Delta_Scuti_variables
#Stars_with_proper_names
Altair （/ælˈtɛər/） designated α Aquilae （Latinised to Alpha Aquilae, abbreviated Alpha Aql, α Aql）, is the brightest star in the constellation of Aquila and the twelfth-brightest star in the night sky.
It is currently in the G-cloud—a nearby interstellar cloud, an accumulation of gas and dust.
Altair is an A-type main-sequence star with an apparent visual magnitude of 0.
77 and is one of the vertices of the Summer Triangle asterism （the other two vertices are marked by Deneb and Vega）.
It is 16.
7 light-years （5.1 parsecs） from the Sun and is one of the most visible stars to the naked eye.
Altair rotates rapidly, with a velocity at the equator of approximately 286 km/s.
This is a significant fraction of the star's estimated breakup speed of 400 km/s.
A study with the Palomar Testbed Interferometer revealed that Altair is not spherical, but is flattened at the poles due to its high rate of rotation.
Other interferometric studies with multiple telescopes, operating in the infrared, have imaged and confirmed this phenomenon.
Altair is the brightest star in the constellation Aquila α Aquilae （Latinised to Alpha Aquilae） is the star's Bayer designation.
The traditional name Altair has been used since medieval times.
It is an abbreviation of the Arabic phrase النسر الطائر （the right, first word having forms from Al Nesr, ranging to An-nisr） Al-ta'ir, "the flying （eagle）".
In 2016, the International Astronomical Union organized a Working Group on Star Names （WGSN） to catalog and standardize proper names for stars.
The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN, which included Altair for this star.
It is now so entered in the...