Kepler-1652 b is a planet about 1.6 times Earth's width in the habitable zone of a red dwarf about 820 light-years away, the range of distances where liquid water could last on a surface. It crosses in front of its star every 38.1 days and receives about 80 percent of the light Earth gets from the Sun.
NASA's Kepler space telescope first flagged it as a candidate, KOI-2626.01, from the small dips in starlight it causes. It was confirmed and given its name in 2017 by a team led by Guillermo Torres. Most small Kepler planets cannot be weighed, so the team validated it statistically, with a method called BLENDER, by showing that a planet explains the signal far better than any other cause. They required at least 99.73 percent confidence, and Kepler-1652 b reached about 99.8 percent. They also used high-resolution imaging and spectra of the star.
Their imaging found two faint stars very close to Kepler-1652 on the sky. That matters, because a transit gives a planet's size only in proportion to the star it crosses. If the planet orbits the main star, it is about 1.6 times Earth's width, small enough that it could be rocky. If it orbited one of the companions, it would be considerably larger. The team took that possibility into account and listed Kepler-1652 b among seven planets with a better than 50 percent chance of being both smaller than twice Earth's width and in the habitable zone. Its estimated equilibrium temperature, set by starlight alone, is about 268 kelvin. Its mass has not been measured.