Scientists Watch the Birth of a Planet Forming from the Disk Around a Star

Scientists are taking a closer look at the birth of a planet. They've discovered what may be evidence of a planet forming around a star that's just 335 light-years from Earth.

The scientists first spotted the possible birth while they were studying the protoplanetary disk around a star known as HD 100546. A protoplanetary disk is a large disk of material that orbits a newly formed star. This disk can actually help spur the creation of an entire planetary system. In this case, the scientists examined the warm gas in the disk using a technique called spectro-astrometry, which allowed them to detect small changes in the position of the moving gas.

While studying the disk, the scientists discovered an extra source of gaseous emissions from carbon monoxide molecules that could not be explained by the protoplanetary disk alone. By tracking the changes in velocity and position of this extra emission, the researchers showed that it was orbiting the young star. It's very possible that this material may be orbiting a very young planet that's still forming.

Intrigued by this, the scientists investigated the emissions a bit further with modeling and additional data. They found that if it's a young planet, it's likely forming into a gas giant at least three times the mass of Jupiter. It's possible that material from the large protoplanetary disk is feeding into the circumplanetary disk, which then feeds onto the growing planet.

"These results provide a rare opportunity to study planet formation in action," said John Carr, one of the researchers, in a news release. "Our analysis strongly suggests we are observing a disk of hot gas that surrounds a forming giant planet in orbit around the star. While such circumplanetary disks have been theorized to surround giant planets at birth and to control the flow of gas onto the growing planet, these findings are the first observational evidence for their existence. If our interpretation is correct, we are essentially seeing a planet caught in the act of formation."

The scientists plan to continue to monitor this region in order to get a better sense of planet formation. This, in turn, could reveal a bit more about the way planets in our own solar system developed.

The findings are published in The Astrophysical Journal.