In 2026, astronomers confirmed a new planet called HIP 54515 b orbiting a distant star. It is a giant world in almost every sense, from its enormous size to the vast sweep of its orbit. Getting to know it helps us understand just how varied planets in our galaxy can be.
Where in Space Is HIP 54515 b?
HIP 54515 b lives around a star called HIP 54515. That star sits about 270 light-years from Earth. A light-year is the distance light travels in one year — roughly 9.5 trillion kilometres. So 270 light-years is an almost impossible distance to picture. Even our fastest spacecraft today would take millions of years to get there.
The star’s name comes from a catalogue called the Hipparcos catalogue, which mapped the positions of many stars across our sky. When you see “HIP” at the start of a star’s name, that is usually where it comes from. You can explore many worlds like this one in our atlas of known exoplanets.
A World of Remarkable Size
HIP 54515 b is not a small place. Its radius — that is, the distance from the centre of the planet to its surface — is about 12.2 times the radius of Earth. That means if you could slice it in half and lay Earth beside it, Earth would look tiny in comparison.
Its mass tells an even bigger story. Mass is how much matter a planet contains. HIP 54515 b has a mass of roughly 5,626 times the mass of Earth. To put that in some context, Jupiter — the biggest planet in our own solar system — is about 318 times Earth’s mass. So HIP 54515 b is far more massive than Jupiter.
In fact, scientists place this object right at the edge of a category called a brown dwarf. A brown dwarf is an object that formed like a star but never grew massive enough to shine as one. At this mass, HIP 54515 b sits in a range where the line between “very massive planet” and “failed star” gets a little blurry. Scientists are still working out exactly how to classify objects in this range. For now, the NASA Exoplanet Archive lists it as a planet.
The Longest Year You Can Imagine
One of the most striking things about HIP 54515 b is how long it takes to travel once around its star. One full orbit — what we would call its year — takes about 33,000 Earth days. That is roughly 90 Earth years for a single trip around its sun.
This tells us the planet is orbiting very far from its host star. In our own solar system, Neptune is the farthest known planet from the Sun, and it takes about 60,000 Earth days to complete one orbit. HIP 54515 b’s year is shorter than Neptune’s, but it still points to a world circling at a great distance from its star.
Because it is so far out, the planet receives very little warmth from its star. Scientists haven’t yet measured how cold or warm HIP 54515 b actually is, but a world at such a great distance is likely to be very cold indeed.
How Scientists Spotted It
Finding exoplanets — planets outside our solar system — is hard. Most are found by watching the light from a star dim slightly as a planet crosses in front of it. But HIP 54515 b was found a different way: direct imaging.
Direct imaging means scientists actually captured light coming from the planet itself, or at least reflected from it, using a powerful telescope. This method works best for large, bright objects orbiting far from their stars, because those planets are easier to separate from the star’s glare. HIP 54515 b fits that description well: it is massive and sits far out in its system.
Direct imaging is one of the rarest ways to find a planet. It requires careful blocking of starlight and very sensitive equipment. Because of this, only a small number of exoplanets have been confirmed this way. You can see how discovery methods have changed over time on our discovery timeline.
What Kind of Star Does It Circle?
The star HIP 54515 has a surface temperature of about 8,100 Kelvin. Kelvin is a scale scientists use for temperature; 8,100 K is extremely hot. Our own Sun has a surface temperature of roughly 5,800 K, so HIP 54515 runs hotter and likely appears whiter or slightly blue-white to the eye, rather than the warm yellow of our Sun. Stars in this temperature range tend to be more massive than our Sun, though scientists haven’t published all the details of this particular star yet.
One Planet, Many Questions
So far, HIP 54515 b is the only known planet in this system. Whether more planets are hiding there, closer in or at different distances, is something astronomers haven’t answered yet. Scientists also haven’t measured the planet’s atmosphere, its exact temperature, or what it is made of on the inside. Those are genuinely hard things to measure from 270 light-years away.
What we do know is that HIP 54515 b adds one more piece to the big puzzle of how planets form and grow. Giant worlds on wide, distant orbits are still not fully understood. Each new confirmed example gives scientists a little more to work with. HIP 54515 b, strange and far away as it is, earns its place in that conversation.