Zeta Aquilae

39 L ☉

Deneb el okab Australis ( from Arabic ذنب العقاب, DMG ḏanab al - ʿ uqāb, tail of the eagle ' ) is the name of the star ζ Aquilae (Zeta Aquilae ) in the constellation Aquila. The star Epsilon Aquilae is distinguished with the proper name Deneb el okab Borealis of Zeta Aquilae.

Zeta Aquilae is to Alpha Aql ( Altair ) and Gamma Aql ( Tarazed ) of the third brightest star in the constellation Aquila. He is a dwarf star of spectral type A0 and has an apparent magnitude of 2.99 mag. Its distance is about 83 light-years. It rotates unusually fast with about 165fachen speed of the sun. Hence its period of rotation is calculated to only about 16 hours, which identifies him as a very young star.

Zeta Aquilae has two low luminosity companion of spectral type M. The most detailed is about 12.0 light- like and 6.5 arcsec from the main component, so that it needs to orbit at least 800 years. The outer companion is about 11.8 light- like and 159 arcsec from the main star; but he could also just be an optical double star, ie seen from Earth just happens to be near the main component.