Chi Cygni Pulsations (VIDEO) Center for Astrophysics | Harvard & Smithsonian This video is under embargo. Please login to access this video. Caption This movie combines infrared images of the surface of Chi Cygni, obtained with IOTA, with visual brightness measurements provided by the American Association of Variable Star Observers. Chi Cygni demonstrates a 408-day-period of expanding and dimming, followed by contracting and brightening. Credit Sylvestre Lacour, Observatoire de Paris Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.