Gl 725 B c is a super-Earth in the habitable zone of Gl 725 B, a small red dwarf about 11.5 light-years away. The habitable zone is the range of distances where a planet could keep liquid water on its surface. Gl 725 B c orbits every 37.9 days and has a minimum mass of about 3.5 Earth masses. Its star has a companion, Gl 725 A, which has a planet candidate of its own, Gl 725 A b.
It was announced in 2026 by a team led by M. Ould-Elhkim, using SPIRou, a spectrograph on the Canada-France-Hawaii Telescope that measures infrared light. They used the radial velocity method, which detects the slight back-and-forth motion a planet's gravity gives its star. Red dwarfs are bright in the infrared, but there Earth's own atmosphere absorbs light at many wavelengths, and those features can distort the measurements. The team developed and tested a correction method called WAPITI, and showed that it recovers planetary signals that would otherwise be hidden or skewed.
With the correction applied, they found two signals. The outer one, Gl 725 B c, they confirmed as a planet. An inner signal at 4.77 days, which would be a planet of about 1.5 Earth masses, remains a candidate, Gl 725 B b. They also measured the star's rotation period at about 105 days, well apart from the planets' periods. Because Gl 725 B c has not been seen crossing its star, only its minimum mass is known, not its size, and whether it is rocky or has an atmosphere is an open question.