View of the field surrounding HR 8799.

In the new findings, the planets are 24, 37, and 67 times the Earth-Sun separation from the host star. The farthest planet in the new system orbits just inside a disk of dusty debris, similar to that produced by the comets of the Kuiper Belt of our solar system (just beyond the orbit of Neptune at 30-50 times Earth-Sun distance).

"HR8799's dust disk stands out as one of the most massive in orbit around any star within 300 light- years of Earth," said UCLA's Ben Zuckerman.