HD 48265 c is a planet that no telescope has ever photographed directly. It sits 295 light-years away, hidden in the glare of its host star. Yet scientists know it exists, and they even know quite a lot about it — all because of clever tricks using starlight.
Where HD 48265 c Lives
The planet orbits a star called HD 48265. That name comes from a catalogue — a giant numbered list astronomers use to keep track of stars. HD 48265 is a star a little like our own Sun. Its surface temperature is 5,805 K (K stands for Kelvin, a unit scientists use to measure very high temperatures — 5,805 K is close to the Sun’s surface temperature of about 5,778 K).
The star is 295 light-years from Earth. A light-year is the distance light travels in one year, which is about 9.5 trillion kilometres. That means the light reaching your eyes from HD 48265 left the star roughly 295 years ago, back when the 1700s were just beginning.
So far, scientists have found two planets in this system. HD 48265 c is one of them. The other is called HD 48265 b. Together, these two worlds make up everything we currently know about that distant solar family.
A Planet of Surprising Size
HD 48265 c is a very large world. Its radius — the distance from its centre to its surface — is about 12.9 times Earth’s radius. To get a feel for that, imagine lining up nearly 13 Earths side by side across the planet’s middle.
Its mass is even more striking. Mass is how much matter, or “stuff”, an object contains. HD 48265 c has a mass around 1,414 times that of Earth. For comparison, Jupiter, the biggest planet in our solar system, has a mass of roughly 318 times Earth. That makes HD 48265 c far more massive than Jupiter.
A planet this large and massive is almost certainly a gas giant — a world made mostly of gases like hydrogen and helium, with no solid ground to stand on. Scientists think planets in this size and mass range form in the outer parts of a solar system, where there is plenty of material to build such a large body. But we should be honest: scientists haven’t yet studied HD 48265 c’s atmosphere or exact composition, so those details remain uncertain for now.
A Very Long Year
HD 48265 c takes 10,418 Earth days to complete one orbit around its star. An orbit is one full trip around the star — what we call a “year” on that world. On Earth, a year is 365 days. On HD 48265 c, one year lasts more than 28 of our years.
That tells us something important. Planets that take so long to orbit are usually very far from their star. The farther a planet sits from its star, the longer its journey around it takes. This is the same pattern we see in our own solar system — Jupiter, far from the Sun, takes about 12 Earth years per orbit, while Neptune, even farther out, takes about 165.
Because HD 48265 c is likely quite distant from HD 48265, it probably sits in a cold region of the system. Scientists haven’t measured exactly how far from the star it orbits, so we can’t say precisely how cold conditions might be out there.
How Scientists Found It: The Radial Velocity Method
HD 48265 c was discovered in 2026 using something called the radial velocity method — sometimes nicknamed the “wobble method”. Here is how it works.
Most people picture a planet orbiting a star the way a ball on a string orbits your hand. But that isn’t quite right. In reality, both the planet and the star pull on each other with gravity. The star moves a tiny bit too, tracing a small circle or wobble as the planet tugs it.
When a star wobbles slightly toward Earth, the light it sends us gets compressed — the waves bunch together and shift toward the blue end of the colour spectrum. When the star wobbles away, the light stretches toward the red end. Scientists call this a Doppler shift, named after the scientist who first described the idea with sound. You experience something similar when a fire engine’s siren sounds higher as it approaches and lower as it moves away.
By measuring these tiny colour shifts very carefully, scientists can calculate how massive a planet must be to cause that wobble, and how long it takes to orbit. That is exactly how HD 48265 c was found — not by seeing it, but by reading the star’s tiny movements in its light.
The Transit Method: Another Way to Spot Invisible Worlds
The radial velocity method is not the only trick astronomers use. Another very common technique is the transit method. A transit happens when a planet passes directly in front of its star, as seen from Earth.
When that happens, the planet blocks a small fraction of the star’s light. Sensitive telescopes can detect this tiny dip — sometimes less than one percent of the star’s total brightness. By watching how often the dip repeats and how long it lasts, scientists can figure out how big the planet is and how long its year lasts.
Think of it like watching a moth fly in front of a lamp across the street at night. You can’t see the moth clearly, but you notice the lamp dims just a little for a moment. You could even estimate the moth’s size from how much the light dropped.
As far as we know, HD 48265 c has not been observed by the transit method — its orbit may not line up in a way that lets us watch it cross the face of its star. If you’d like to see how the transit method works in an interactive way, you can explore how astronomers find planets with our visual guide.
What We Still Don’t Know
Even with a mass and radius in hand, HD 48265 c holds many mysteries. Scientists haven’t measured its exact distance from its star, the temperature of its clouds or atmosphere, or whether it has any moons. We don’t know if the second planet, HD 48265 b, orbits closer or farther out, or what kind of world it is.
This is completely normal in exoplanet science. An exoplanet is simply any planet outside our solar system. Most exoplanets are known only through a handful of numbers coaxed out of starlight. The rest is careful thinking, honest uncertainty, and the slow work of building knowledge one measurement at a time. HD 48265 c reminds us that you don’t have to see something directly to start understanding it — and that there is still so much more to learn.