Tabby's Star

Tabby's Star or Boyajian's Star (designated as KIC 8462852 in the Kepler Input Catalog) is a binary star in the constellation Cygnus approximately 1,470 light-years (450 parsecs) from Earth. The system is composed of an F-type main-sequence star and a red dwarf companion. Unusual light fluctuations of Tabby's Star, including up to a 22% dimming in brightness, were discovered by citizen scientists as part of the Planet Hunters project. The discovery was made from data collected by the Kepler space telescope, which observed changes in the brightness of distant stars to detect exoplanets. Several hypotheses have been proposed to explain the star's large irregular changes in brightness, but as of 2024, none of them fully explain all aspects of the resulting light curve. It has been suggested that it is an extraterrestrial megastructure, but evidence tends to discount this suggestion. In September 2019, astronomers reported that the observed dimmings of Tabby's Star may have been produced by fragments resulting from the disruption of an orphaned exomoon.