Astronomers have made a groundbreaking discovery about the formation of 'super Jupiters' around distant stars. Using data from NASA's James Webb Space Telescope (JWST), researchers have found new evidence that challenges traditional theories of planet formation.
The study focused on a planetary system 133 light-years away, containing four giant planets, each between five and ten times the mass of Jupiter. These planets orbit far from their star, at distances ranging from 15 to 70 astronomical units (AU). The star system, known as HR 8799, lies in the constellation Pegasus.
The key to this discovery was the detection of sulfur in one of the planets' atmospheres. Sulfur-containing compounds would exist as solids in the cold disk of material surrounding a young star, suggesting that these planets formed through a different process than previously thought.
A controversial theory, gravitational instability, suggests that some massive planets form more like stars. However, the new findings indicate that these distant super Jupiters likely formed through a gradual process similar to Jupiter's formation. This challenges the idea that these planets formed through gravitational instability.
The research, published in the journal Nature Astronomy, also revealed that the three innermost planets in the system contain higher levels of heavy elements, such as carbon and oxygen, compared to their parent star. This further supports the idea that these planets formed through the gradual buildup of solid material.
The planets in HR 8799 are extremely faint, making them difficult to study. JWST's spectrograph was not initially designed for observing such faint planetary signals next to bright stars. To overcome this, researchers developed new data-processing techniques and refined atmospheric models to interpret the complex spectral signatures.
This discovery expands the boundaries of where core accretion can occur. It suggests that even massive planets far from their host star can grow through the same gradual process that shaped Jupiter. As JWST continues to observe distant worlds with unprecedented detail, scientists expect to gain even more insights into the formation of planetary systems.
