Kepler-296 f is the outermost of five planets around Kepler-296, a pair of red dwarfs about 550 light-years away, and the coolest. It crosses in front of its star every 63.3 days. NASA's Kepler space telescope found it, with its four siblings, by catching the small dip in starlight at each crossing. The five were confirmed in 2014 as part of a large study led by Jason Rowe.
Its most interesting property is where it orbits. In 2015 a team led by Thomas Barclay worked out which of the two stars the planets circle, a question that matters because a transit's depth gives a planet's size only once you know which star is being dimmed. They concluded that all five orbit the brighter star, Kepler-296 A. On that basis, Kepler-296 f is about 1.8 times Earth's width and receives about 0.62 times the light Earth gets from the Sun. Together with its inner neighbour Kepler-296 e, which receives about 1.4 times Earth's light, it lies within or close to the star's habitable zone, the range of distances where liquid water could last on a surface.
Whether it could actually hold water is unknown. Its mass has never been measured; the NASA Exoplanet Archive's figure of about 3.9 Earth masses is an estimate based on its size. A planet 1.8 times Earth's width could be a large rocky world or one wrapped in a thick envelope of gas, and nothing is known about its atmosphere.