Chi Cygni is a giant-star Mira variable that can reach magnitude 3.5 for some time during a 408.05-day variation period, from magnitude 13.4. Chi Cygni is a rare class S (S6) star, highly enriched in zirconium, that is about 345 light years away. Chi Cyg radiates the power of roughly 3000 Suns from a cool, reddish surface (3000 Kelvin or below) that has expanded to a diameter 300 times that of the Sun.
The star is found between eta and beta Cygni and has one of the largest variations in magnitude known.