A Planet That Shouldn't Exist: This Distant World Has An Unexpected Temperature
- 28.09.2026, 20:05
Astronomers have discovered water on the giant planet HATS-6 b.
Scientists used the Webb Space Telescope to study the planet HATS-6 b, a gas giant located 500 light-years away from us. Water, ammonia, and methane were detected in the planet’s atmosphere. It also turned out that this planet is significantly colder than scientists had expected. In fact, a planet like this wasn’t even supposed to exist. The study was published in the *Astronomical Journal*, according to Phys (translation - “Focus”).
The planet HATS-6 b is similar in size to Jupiter, the largest planet in the Solar System, and is also a gas giant. This distant planet orbits a red dwarf star—smaller and cooler than the Sun.
Planets form from the gas and dust left over from a star’s formation. The smaller the star, the smaller the planets that can form around it. But the enormous size of HATS-6 b defies this rule. Astronomers say that such a planet should never have formed, since there wasn’t enough material for its formation. And yet it—and 40 other planets like it—exist. Astronomers are still trying to understand how they came to be.
During their research, scientists detected water, methane, ammonia, and carbon dioxide (carbon dioxide). While hydrogen and oxygen—the components of water—as well as carbon have previously been found in the atmospheres of giant planets outside the Solar System, ammonia, which consists of nitrogen and hydrogen, is found very rarely. Therefore, this discovery is very important for understanding the composition of such planets.
Nitrogen-containing compounds, such as ammonia, are expected to be present on cold giant planets. But HATS-6 b orbits close to its star and completes a full orbit in just 3 Earth days. This means it must be hot there. Calculations had shown that the planet’s temperature should be around 425 degrees Celsius. But new measurements revealed a temperature of 120 degrees Celsius.
If this planet is cooler, it means that something is reflecting a significant portion of the star’s light back into space, preventing it from heating HATS-6 b, scientists say. Now we need to figure out what that is.