Young sunlike system reveals comets may carry water toward forming planets

A team of astronomers from Lund University in Sweden has discovered exocomets orbiting a young star similar to our sun, suggesting a possible mechanism for transporting water from the outer regions of a planetary system to where planets form. The system, PDS 70, is about 5 million years old and located about 370 light-years from Earth. The star is slightly cooler than the sun, and the researchers observed sodium gas variations that indicate comets passing in front of the star. This is the first time such evidence has been seen in a cool, young star system.

The study shows that comets may be responsible for transporting water to the inner parts of the planetary system, where planets can form. The researchers analyzed data from 2018 and detected sodium gas moving at several kilometers per second relative to the star, a pattern consistent with comets passing in front of a star. When a comet approaches its star, it heats up and the ice on its surface turns directly into gas—a process known as sublimation. The gas can then leave a measurable imprint in the star's light. The findings suggest that comets can transport water and other volatile substances from the outer regions of a planetary system to the inner regions where planets form.

The discovery provides insight into how water might have originated on Earth. Water-rich asteroids and comets are two possible sources of Earth's water. PDS 70 offers a unique opportunity to study a similar process while a planetary system is still in its early stages of development. Researchers believe that if further planets are found in the system, it will help clarify how water and other building blocks of planets are transported. The study was published in Nature Communications.

AI-generated summary of the original article — see the source for the full story.