In 2026, astronomers added a new world to our growing list of known planets beyond our solar system. That world is TOI-1756 b, a super-Earth sitting 283 light-years away. It is already raising interesting questions about what rocky — or not-so-rocky — worlds can look like.
Where in the Sky Do We Find TOI-1756 b?
TOI-1756 b orbits a star called TOI-1756. The whole system is 283 light-years from Earth. A light-year is the distance light travels in one year — about 9.5 trillion kilometres. So 283 light-years is an almost unimaginably large gap. We cannot visit this planet any time soon, but we can still learn a great deal about it just by studying the light from its star.
If you want to explore how this planet fits among the thousands of worlds astronomers have found so far, the Atlas is a good place to browse.
What Kind of Star Does TOI-1756 b Orbit?
The host star, TOI-1756, is much cooler than our own Sun. Its surface temperature is 3,892 K. (K stands for kelvin, a unit scientists use to measure temperature. Zero kelvin is the coldest anything can be. Room temperature on Earth is about 294 K.) Our Sun’s surface sits at around 5,778 K, so TOI-1756 is noticeably cooler and almost certainly smaller and dimmer too.
A star this cool is likely what astronomers call a red dwarf — a small, faint star that burns through its fuel slowly and can last far longer than our Sun. Red dwarfs are the most common kind of star in the Milky Way. Many of the exoplanets — planets orbiting stars other than our Sun — that scientists study closely orbit red dwarfs, simply because there are so many of them.
Orbiting a red dwarf comes with some interesting trade-offs. These stars are long-lived and stable over huge stretches of time, which sounds promising. But they can also send out powerful bursts of radiation, especially when they are young. Whether TOI-1756 is the calm or stormy type, scientists haven’t said yet.
Size, Mass, and What That Tells Us
TOI-1756 b earns the label super-Earth because it is bigger and heavier than our planet, but not nearly as large as Neptune. Its radius — the distance from its centre to its surface — is 1.94 times Earth’s radius. Think of it as nearly twice as wide as Earth. Its mass is 4.43 times Earth’s mass, meaning it has more than four times the stuff packed into it.
Those two numbers together are really useful. When scientists know both the size and the mass of a planet, they can work out its density — how tightly packed that mass is. A planet with a high density for its size is probably made mostly of rock or metal. A lower density might mean it has a thick atmosphere or a lot of water mixed in.
For TOI-1756 b, the numbers sit in an interesting middle zone. Scientists think it could be a rocky world with a thin or moderate atmosphere, or it might hold a notable amount of lighter materials like water or gas. Right now, we honestly aren’t sure. More observations would be needed to say with confidence what this planet is really made of.
A Scorching, Fast Year
One thing is very clear about TOI-1756 b: it is hot. Its likely temperature is around 696 K, which works out to about 423 degrees Celsius. That is hot enough to melt lead. For comparison, the average surface temperature on Venus — the hottest planet in our solar system — is around 465 degrees Celsius, so TOI-1756 b is in a similar, very extreme range.
This heat makes sense when you consider how close the planet sits to its star. One full orbit — one year on TOI-1756 b — takes just 2.78 Earth days. That is less than three of our days. The planet is hugging its star very tightly, which means it receives a huge amount of radiation and heat. A place like this sits well outside the habitable zone, the range of distances from a star where liquid water could exist on a planet’s surface. As far as we know, TOI-1756 b is far too hot for liquid water.
How Scientists Found It
TOI-1756 b was confirmed in 2026 using the transit method. This technique works by watching a star very carefully. When a planet passes in front of that star — as seen from Earth — it blocks a tiny fraction of the starlight. The star appears to dim slightly, then brighten again as the planet moves on. By measuring how much the light dips and how often it happens, scientists can figure out the planet’s size and how long its orbit takes.
The transit method has been one of the most successful tools in the search for exoplanets. You can read more about the history of these discoveries on our Discovery Timeline.
What We Still Don’t Know
TOI-1756 b is the only planet scientists have found in this system so far. That does not mean it is alone — other worlds could be hiding there, too small or at the wrong angle for us to detect yet. Scientists also haven’t measured the planet’s atmosphere, if it has one at all. At such high temperatures, a light atmosphere might have been stripped away long ago by radiation from the star. Or perhaps a heavier mix of gases clings on. We simply don’t know yet.
TOI-1756 b is a reminder that the universe keeps offering us new puzzles. Each world we find, even a scorching one with no chance of life as we know it, teaches us something about how planets form, how stars shape their neighbours, and how much variety exists out there among the stars.