Astronomers recently discovered new evidence that explains how giant “superJupiters” form around distant stars.

Using data from NASA’s James Webb Space Telescope Researchers studied a planetary system 133 light-years away and found that the giant planet likely formed in a similar way to Jupiter, according to (JWST).

The discovery focuses on the detection of sulfur in one of the planet’s atmospheres. This discovery provides important clues about how these giant worlds came to exist.

huge distant star system

The HR 8799 star system is located in the constellation Pegasus. It has four giant planets, each with a mass 5 to 10 times that of Jupiter. These planets orbit at great distances, ranging from 15 to 70 astronomical units from their stars. For comparison, Earth is only one astronomical unit from the Sun.

Because both of these planets are so large and located so far from their stars, astronomers have always debated how they formed. The traditional theory of planet formation, known as nuclear accretion, suggests that planets grow gradually. Small dust particles stick together to form pebbles, which form the core of the rock. When the core becomes large enough, it attracts surrounding gas and ice, eventually forming a gas giant.

But another theory, called gravitational instability, suggests that some giant planets have a star-like shape. Many scientists suspected that distant superJupiters could form in this way. New findings suggest otherwise.

Important clues about sulfur

The researchers focused specifically on planet HR 8799 c. Using JWST, they analyzed the planet’s atmosphere and detected sulfur as hydrogen sulfide.

This detail is important because sulfur-containing compounds can exist as solids in the cold disk surrounding young stars. This means that sulfur may have been incorporated into the growing rocky core before the planet collected large amounts of gas.

In addition to sulfur, the system’s three innermost planets were found to contain more heavy elements such as carbon and oxygen compared to their parent stars. This enrichment further supports the idea that these planets formed by gradual accumulation of solid material. These discoveries were published in the journal Nature Astronomy.

HR 8799’s planet is approximately 10,000 times fainter than its star, making it extremely difficult to study. JWST’s spectrometer was not originally designed to observe such faint planetary signals next to bright stars.

To overcome this, researchers have developed new data processing techniques to separate the planet’s light. They also refined atmospheric models to interpret the complex spectral features captured by the telescope. The high sensitivity of JWST has made it possible to detect molecules that have not been identified anywhere else in the world.

Expanding the limits of planet formation

This discovery pushes the current limits within which nuclear accretion can occur. Previously, it was unknown whether rocky cores could form this far from a star. The HR 8799 system suggests that even giant planets far from their host stars can grow through the same gradual process that formed Jupiter.

These discoveries provide valuable new data for astronomers studying planet formation. As JWST continues to observe distant worlds in unprecedented detail, scientists hope to gain even more insight into how planetary systems form.