For the first time, we have a clear and detailed view of planet formation in a distant solar system, thanks to the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile.
The new image captures the birth of planets in great detail in a solar system about 450 light-years away from Earth in the constellation Taurus.
These images not only show how planets form, but also confirm existing theories that we have about planet formation.
Theory states that stars form from clouds and dust that collapse because of gravity. Those dust particles stick together and then grow, becoming larger, eventually finding their way to a protoplanetary disk, which is a rotating disk that exists around a young star. It is here where planets are born. Once planets get bigger, the disk's shape changes, creating concentric rings, with gaps between them where planets have orbited the star and kicked out debris from the disk.
The image shows a young star, called HL Tau, surrounded by many concentric rings, separated by gaps. This suggests that planets are forming within its disk. This is the clearest picture we've ever seen of planet formation, save for previous images created by artists and computers, and it confirms what we know about how planets form within a solar system.
"This new and unexpected result provides an incredible view of the process of planet formation," says Tony Beasley, director of the National Radio Astronomy Observatory (NRAO). "Such clarity is essential to understand how our own Solar System came to be and how planets form throughout the Universe,"
However, this image also surprised astronomers. The star at the center of this solar system is relatively young, only about a million years old, and therefore, shouldn't yet have planet formation capabilities.
"These features are almost certainly the result of young planet-like bodies that are being formed in the disk," says ALMA Deputy Director Stuartt Corder. "This is surprising since HL Tau is no more than a million years old and such young stars are not expected to have large planetary bodies capable of producing the structures we see in this image."
This suggests that although our theories of planet formation are correct, we may need to revise our theories about stars' ages when planets begin forming in their systems.
ALMA captured the image as astronomers tested its high-resolution capabilities. It looks like ALMA not only passed the test, but exceeded it.
[Photo Credit: National Science Foundation, A. Khan]
