Kepler-968: A Cool, Older Star With Three Small Worlds

Kepler-968 is a star located 947 light-years away. It is 2.14 billion years old and has a reported mass estimate of 0.76 solar masses, which is smaller than the Sun's. Its reported radius estimate is 0.7 solar radii, also smaller than the Sun's, and its reported temperature of 4600 K is cooler than the Sun's. Three planets orbit this host: Kepler-968 b, Kepler-968 c, and KOI-1833 d. All three were found by the transit method, in which a planet passes in front of its star from our viewpoint and causes a small dip in observed brightness.

Kepler-968 b and Kepler-968 c are both Super-Earths, a size class reaching 2.5 times Earth's radius. Kepler-968 b has a reported radius estimate of 2 Earth radii, larger than Earth's, and an orbital period of 3.69 days. Kepler-968 c has a reported radius estimate of 1.69 Earth radii, larger than Earth's, and an orbital period of 5.71 days. Both were discovered in 2016.

KOI-1833 d is Neptune-like, a size class reaching 4 times Earth's radius. It has a reported radius estimate of 2.58 Earth radii, larger than Earth's, and an orbital period of 7.69 days. Its mass is a reported upper limit of 11.02 Earth masses. It was discovered in 2021.

Among the listed planets, Kepler-968 b has the shortest year by reported estimates at 3.69 days, Kepler-968 c has the second-shortest year at 5.71 days, and KOI-1833 d has the longest year at 7.69 days. In radius, Kepler-968 c has the smallest at 1.69 Earth radii, Kepler-968 b has the second-smallest at 2 Earth radii, and KOI-1833 d has the largest at 2.58 Earth radii.