Unseen Newborn Planets Are Stirring Up Dust Around a Young Star
Our universe is so capricious it sometimes likes to play a game of hide and seek. In 2017, astronomers were surprised to see a huge shadow sweeping across a disk of dust and gas encircling the nearby young star TW Hydrae. The shadow is cast by an inner disk of dust and gas that is slightly tilted to the plane of the outer disk. The shadow can only be clearly seen because the system is tilted face-on to Earth, giving astronomers a bird's-eye view of the disk as the shadow sweeps around the disk like a hand moving around a clock.
But a clock has two hands (hours and minutes) sweeping around at different rates. And, it turns out, so does TW Hydrae. Astronomers used Hubble to find a second shadow emerging from yet another inner disk, that is tilted to the two outer disks. So, the system looks increasingly complicated with at least three nested disks slightly tilted relative to each other. The disks are proxies for unseen planets around the star. Each planet is gravitationally pulling on material near the star and warping what would have been a perfectly flat, pancake-shaped disk if no planets were present. This is not a surprise because the planets in our solar system have orbital planes that vary in tilt by a few degrees from each other. TW Hydrae gives astronomers a ringside seat to how our solar system may have looked during its formative years.
Find additional articles, images, and videos at HubbleSite.org
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