Astronomers Discover Fluffy Disk around Baby Star

Astronomers are getting a better look at a baby star, called RY Tau. They've used Subaru Telescope's High Contrast Instrument for the Subaru Next Generation Adaptive Optics (HiCIAO) to get a closer glimpse at a "fluffy" layer of material hovering above the disk around the young star.

Young stars are known for the disks of material surrounding them. This material is usually what's left over from star formation. Consisting of dust and gas, these disks often become sites of planet formation, which makes them particularly interesting to astronomers. Called "protoplanetary disks," these giant clouds of dust and gas can clump together to eventually form rocky, Earth-like planets.

RY Tau itself is located about 460 light-years away from Earth in the constellation Taurus. Only about half a million years old, the star possesses a disk that has a radius of about 10 billion kilometers, which is a few times larger than the orbit of Neptune in our own solar system. In this latest study, the researchers were able to capture images of the disk surrounding the star with their instruments.

What did they find? It turns out that the "fluffy" layer above the disk was responsible for the scattered light observed in an infrared image. This scattered light revealed the structure of the surface of the disk, which is very small in scale and difficult to observe, even with large telescopes. Unlike many other protoplanetary disks, the disk emission in this one was offset from the center of the star. The astronomers also found out information about the vertical structure of the disk.

This fluffy layer is relatively unusual. But the researchers have an explanation for why it's present around this star. The scientists believe that it's a remnant of the dust that fell onto the star and the disk during earlier stages of formation. In other stars, this layer dissipates. But RY Tau may still have the layer due to how young it is.

The findings are published in The Astrophysical Journal.