Tabby Star's Mysterious Fade (IMAGE) Columbia University Caption A new Columbia study suggests chunks of an exomoon's dusty outer layers of ice, gas, and carbonaceous rock may be accumulating in a disk surrounding Tabby's Star, blocking the star's light and making it appear to gradually fade. Credit NASA/JPL-Caltech 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.