A false color image of the pulsating red giant star Chi Cygni, as imaged in the infrared by the Infrared Optical Telescope Array. Four different times of the pulsation are shown, and hot spots on the star's surface can be seen. At its smallest,
the star's diameter is about 300 million miles.
Credit: IOTA, and Lacour et al., 2009 Low Resolution Image (jpg)