Chi Cygni

0.4 to 10,000 L ☉

Chi Cygni ( χ Cygni ) is a variable star of type Mira in the constellation Cygnus. Its variability was discovered in 1686 by Gottfried Kirch. He was thus to Mira discovered the second star of this Mutable class.

With an average period length of 408 days Chi Cygni shows the largest variations in the apparent brightness of all Mirasterne. This reached extreme values ​​of 3.3 and 14.3 might like. Thus Chi Cygni is minimum with telescopes with an aperture ( opening) of about 30 centimeters visible as it can often be seen with the naked eye at a maximum.

Because flow out as a gas from the surface, inter alia, CO and SiO, and the star surrounded as a cloud of molecules and silica dust, there is a color excess, i.e., the radiation absorbed by the cloud, the star is emitted again in the infrared spectrum. The infrared part of the radiation is therefore higher than would be expected according to Planck's radiation law for the temperature of the star.