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Sadr (Gamma Cygni)





Gamma Cygni (Sadr)
Gamma Cyg and IC 1318.
Image: Ed Szczepanski

The third brightest star in the constellation Cygnus and the center star of the Northern Cross. Sadr lies at the northern end of the Great Rift with a spectacular portion of the Milky Way as a backdrop. Its name comes from an Arabic phrase meaning "the hen's breast."

Unlike most supergiants, which are either fairly hot or quite cool and reddish, Sadr is yellow-white and in the mid-temperature range. It has left the main sequence and is now near a region of temperature and luminosity in which stars become unstable and pulsate.


visual magnitude 2.23
absolute magnitude -6.12
spectral type F8Ib
surface temperature 6,500 K
luminosity 65,000 Lsun
mass 12 Msun
distance 1,520 light-years
position R.A. 20h 22m 13.7s,
Dec. +40 15' 24"


Related category

   • NOTABLE STARS