Wolf 1069 b
Wolf 1069 b is a terrestrial planet orbiting the M5.0 V star Wolf 1069 in the constellation Cygnus. It lies about 31 light-years from Earth and was discovered in 2023 using the radial velocity method. It orbits within the habitable zone of its star — the region where liquid water could exist on a planet's surface.
Is Wolf 1069 b in the Habitable Zone?
Wolf 1069 b orbits inside the conservative habitable zone of Wolf 1069 — the region where a rocky planet could sustain liquid water on its surface. This makes it one of the most interesting known exoplanets in the search for life.
Habitable zone of Wolf 1069: 0.045–0.118 AU (conservative: 0.056–0.111 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on Wolf 1069 b
The equilibrium temperature of Wolf 1069 b is about 250 K (-23 °C) — in a range broadly comparable to Earth, whose equilibrium temperature is 255 K. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 0.65 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on Wolf 1069 b — one full orbit around Wolf 1069 — lasts 15.6 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.067 AU — closer to its star than Mercury is to the Sun.
How Was Wolf 1069 b Discovered?
Wolf 1069 b was discovered in 2023 using the radial velocity method, with observations from Calar Alto Observatory.
The radial velocity method measures the subtle wobble of a star caused by the gravitational pull of an orbiting planet, visible as periodic shifts in the star's light spectrum. The size of the wobble reveals the planet's minimum mass.
How Far Away Is Wolf 1069 b?
Wolf 1069 b is 31.3 light-years (9.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1995. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 550,880 years to make the journey.
Earth Similarity Index
The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. Wolf 1069 b scores 0.85, ranking #15 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Wolf 1069
Wolf 1069
- Spectral type
- M5.0 V
- Surface temperature
- 3,158 K (Sun: 5,772 K)
- Mass
- 0.17 M☉
- Radius
- 0.18 R☉
- Luminosity
- 0.0029 L☉
Planetary System
Wolf 1069 b is the only planet known to orbit Wolf 1069 so far.
Wolf 1069 b — Complete Data
| Mass (best estimate) | 1.26 Earth masses |
|---|---|
| Orbital period | 15.56 days |
| Orbital distance | 0.067 AU |
| Equilibrium temperature | 250 K (-23 °C) |
| Stellar irradiation | 0.65× Earth |
| Earth Similarity Index | 0.85 |
| Distance from Earth | 31.3 light-years (9.6 parsecs) |
| Constellation | Cygnus |
| Discovery method | Radial Velocity |
| Discovery facility | Calar Alto Observatory |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2023-02-25. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Wolf 1069 b
Is Wolf 1069 b habitable?
Wolf 1069 b orbits within the habitable zone of Wolf 1069, the region where liquid water could exist on a planet's surface. It sits in the conservative habitable zone — the most promising region for habitability. Whether it is actually habitable depends on its atmosphere and composition, which remain unknown.
How far away is Wolf 1069 b?
Wolf 1069 b is about 31 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 550,880 years to get there.
How long is a year on Wolf 1069 b?
One orbit around Wolf 1069 takes 15.6 Earth days — short enough that 23 of its years would fit into one Earth year.
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