Wolf 1069 b

Wolf 1069 b is an Earth-sized planet orbiting the red dwarf star Wolf 1069. Being located in the habitable zone of its star, Wolf 1069 b is considered a potentially habitable planet, as well as the sixth-closest Earth-mass planet orbiting within its star's habitable zone. The minimum mass of the planet, as measured by the radial velocity method, is 1.26, while its radius is estimated at 1.08. The equilibrium temperature of Wolf 1069 b is -23 °C.

Characteristics
Located about 9.6 pc from Earth, it is one of the closest known exoplanets. The minimum mass of Wolf 1069 b is measured at $15.564 day$— very similar to that of Earth. Its radius is estimated at 1.08 according to mass-radius relationships.

The planet takes about 16 days to fully orbit Wolf 1069, and is located at an average distance of 0.0672 AU from it, which makes it located in its star's habitable zone.

Wolf 1069 b was discovered using radial velocity data from the CARMENES spectrograph at the Calar Alto Observatory, Spain. Its discovery was announced in January 2023, in the journal Astronomy & Astrophyics.

Habitability
Wolf 1069 b is considered a potentially habitable planet, as it orbits in the conservative habitable zone of its star (located between 0.056 and 0.111 astronomical units), in addition to having a mass similar to that of Earth. It is very likely that Wolf 1069 b has a similar composition to Earth (32.5% of iron and 67.5% of silicate), in addition to probably having liquid water on its surface. Located 31 light-years away, it is the sixth-closest Earth-mass planet orbiting in the habitable zone of its host star— only Gliese 1002 b and c, Gliese 1061 b, Teegarden b and Proxima Centauri b are closer. Its equilibrium temperature is calculated at 250 K, and it receives an incident flux from its star equivalent to 65% of what the Earth receives from the Sun.

Despite being considered potentially habitable, the short distance from its star causes Wolf 1069 b to be tidally locked, meaning one side of the planet is always facing its star, while the other is always opposite it. Because it is tidally locked, Wolf 1069 b does not have a day/night cycle like Earth, meaning that one side of the planet is in an eternal day while the other side is in an eternal night.

Host star
Wolf 1069 is a red dwarf that is located 31 light-years from Earth in the northern constellation Cygnus. The star has a slow rotation period, rotating on its own axis every 170 days, while the Sun takes 25 days to complete one rotation. Wolf 1069 is much smaller, cooler and less massive than the Sun, having a mass of 0.167, a surface temperature of 3158 K, and a radius of 0.18 , which makes it one of the smallest stars known. It was discovered in 1920 by Max Wolf.