Wolf 1069 b is a planet orbiting a dim, cool star just 31.3 light-years from Earth. That is close, as far as stars go. Scientists discovered it in 2023, and ever since, researchers have been asking an interesting question: could this world be a place where life might exist?
A Small, Cold World Not Far Away
Wolf 1069 b was found using the radial velocity method. This technique works by watching a star very carefully. When a planet orbits a star, its gravity gives the star a tiny wobble. Scientists can measure that wobble and use it to figure out that a planet is there, even without seeing the planet directly.
The planet sits 31.3 light-years away. A light-year is the distance light travels in one year — about 9.5 trillion kilometres. That is enormous by human standards, but in cosmic terms, Wolf 1069 b is practically a neighbour. It is one of the closer potentially habitable planets scientists have found so far.
One year on Wolf 1069 b lasts just 15.6 Earth days. That is how long it takes to complete one full orbit around its star. It moves much faster than Earth does around our Sun.
What Kind of Star Is Wolf 1069?
Wolf 1069 is a red dwarf — a type of star that is smaller, cooler, and dimmer than our Sun. You can see how cool it is from its surface temperature: 3,158 K. (K stands for Kelvin, a scientific temperature scale. Zero Kelvin is the coldest anything can be. Our Sun’s surface sits at about 5,778 K, so Wolf 1069 is quite a bit cooler.) Red dwarfs glow with a reddish-orange light rather than the bright white-yellow light of our Sun.
Because red dwarfs are so dim, their habitable zone — the band of distances where liquid water on a planet’s surface is possible — sits much closer in than our Sun’s habitable zone does. Wolf 1069 b orbits very close to its star and yet still sits within that zone. That is what makes it interesting to scientists.
Red dwarf stars also live for an extraordinarily long time, far longer than stars like our Sun. Some scientists think that gives any life on their planets more time to develop. But red dwarfs can also send out powerful bursts of energy called stellar flares. These flares could strip away a planet’s atmosphere over millions of years. Whether Wolf 1069 is an especially active flaring star, scientists haven’t fully measured yet.
Size, Mass, and What the Ground Might Be Like
Wolf 1069 b has a radius 1.08 times that of Earth. In other words, it is just slightly wider than our planet — so close in size that if you put them side by side, the difference would be small. Its mass is 1.26 times Earth’s mass, meaning it is a little heavier.
When a planet is close to Earth in both size and mass, scientists think it is likely to be a rocky planet — one with a solid surface, similar to Earth, Mars, or Venus. This is different from gas giants like Jupiter, which are enormous balls of gas with no solid ground to stand on.
Having a rocky surface matters for life as we know it. Life on Earth lives on land, in oceans, and in soil. A solid world gives those kinds of environments somewhere to exist. Scientists haven’t confirmed that Wolf 1069 b is rocky, but its size and mass make that a reasonable working guess.
Temperature and the Habitable Zone
The estimated temperature of Wolf 1069 b is about 250 K, which works out to roughly -23 degrees Celsius. That is cold — colder than a freezer, and similar to a bitter winter day in parts of Canada or Siberia.
At first glance, that sounds too cold for liquid water. Water freezes at 0 degrees Celsius. But this temperature estimate assumes the planet has no atmosphere. An atmosphere is a layer of gas surrounding a planet. Earth’s atmosphere traps some of the Sun’s warmth, raising our average temperature significantly. If Wolf 1069 b has an atmosphere, it could be warmer at the surface than that raw number suggests.
The planet sits inside what scientists call the habitable zone around its star. “In the habitable zone” does not mean a planet has water or life. It simply means the conditions could allow liquid water to exist on the surface — if the planet also has the right kind of atmosphere and other factors line up. It is a promising starting point, not a guarantee.
Tidally Locked: One Side Always Faces the Star
Because Wolf 1069 b orbits so close to its star and completes one orbit in just 15.6 days, scientists think it is likely tidally locked. This means one side of the planet permanently faces the star, while the other side is always in darkness. Our Moon is tidally locked to Earth in the same way — we always see the same face of the Moon.
A tidally locked planet would have a very hot day side and a very cold night side. The zone in between — called the terminator, where day meets night — might be a narrow band where temperatures are somewhere in the middle. Some scientists think this in-between region could be the most liveable spot on such a world. Others point out that without winds moving heat around, the differences could be extreme. We simply don’t know yet.
What an Atmosphere Could Change
Almost every important question about Wolf 1069 b comes back to one thing: does it have an atmosphere, and what is it made of? Scientists haven’t measured this yet. It is very hard to study the atmospheres of small, rocky planets around dim stars with current telescopes.
If the planet has a thick enough atmosphere, it could spread warmth from the day side to the night side, soften the temperature extremes, and raise surface temperatures above freezing in some regions. The right mix of gases — like carbon dioxide or water vapour — could create a gentle greenhouse effect, trapping heat the way a blanket traps warmth. Too much greenhouse effect, though, and a planet becomes dangerously hot, like Venus.
Future telescopes may be able to study this planet’s atmosphere. Until then, we are working with what we have.
What We Still Don’t Know
Wolf 1069 b is one of the more interesting nearby planets scientists have found, and it appears on many most Earth-like worlds comparisons for good reason. But interesting is not the same as confirmed. Scientists don’t yet know whether it has an atmosphere, what that atmosphere contains, whether liquid water exists there, or whether the star’s flares have already made the surface hostile. Only one planet is known in this system so far, and many measurements haven’t been made.
What we can say honestly is this: Wolf 1069 b is a rocky-sized world, close to Earth in size and mass, sitting in the zone where liquid water could exist around its star, and it is close enough that future science might actually be able to study it properly. That makes it worth watching carefully.