Which exoplanet orbits the red dwarf Ross 128?

Ross 128 b is the exoplanet that orbits the red dwarf Ross 128.

Astronomers discovered Ross 128 b in 2017 using the HARPS spectrograph at ESO’s La Silla Observatory in Chile. Rather than observing a transit, they detected the planet through the star’s radial-velocity wobble—the gravitational tug of the orbiting planet shifts the star’s spectral lines.

Ross 128 b is about 11 light-years away and was, at discovery, the second-closest known Earth-size exoplanet after Proxima Centauri b. Its minimum mass is about 1.4 times Earth’s, and it completes an orbit in only 9.9 days because it circles its faint, cool star at a much smaller distance than Earth orbits the Sun.

The planet receives roughly 1.38 times Earth’s incoming stellar energy and lies near the inner edge of its star’s habitable zone. That does not establish surface habitability. Ross 128 b does not transit from our viewpoint, so studying its atmosphere is more difficult than for a planet that crosses its star’s disk.