Kepler-289
Kepler-289 is a rotating variable star slightly more massive than the Sun, with a spectral type of G2, 2370 light-years away from Earth in the constellation of Cygnus. It hosts a system of multiple exoplanets.
Planetary system
Kepler-289 hosts three transiting planets, discovered using the Kepler space telescope. Two planets, Kepler-289b and Kepler-289c, were confirmed in 2014 as part of a study using statistical validation to confirm hundreds of Kepler candidates. A third planet, Kepler-289d, was found by the Planet Hunters citizen science project, hence the other designation for the system, PH3.Different sources present conflicting models of Kepler-289's planetary system. The discovery paper for planet d says that it has an orbital period of 66 days, and that a 330-day candidate is an alias of the true period of planet d. A 2023 follow-up study also reports a 66-day period for planet d. However, a 2025 study reports a 330-day planet, and says that the 66-day signal "is no longer believed to exist in the data". The NASA Exoplanet Archive lists both a 66-day and a 330-day planet, the latter called Kepler-289e, but no literature source claims the existence of more than three planets in the system.