![]() The suspected planets are located in a region roughly the distance of Jupiter from our Sun. It's like two race cars that are close to each other, but one slowly overtakes and laps the other," said Debes. If one was moving much faster than the other, this would have been noticed in earlier observations. ![]() "It does suggest that the two planets have to be fairly close to each other. Sometimes labels will match up but then one gets ahead of the other. It's sort of like spinning two vinyl phonograph records at slightly different speeds. The disks may be proxies for planets that are lapping each other as they whirl around the star. Hubble is piecing together a holistic view of the architecture of the system. The simplest explanation is that the misaligned disks are likely caused by the gravitational pull of two planets in slightly different orbital planes. It makes the system much more complex than we originally thought," he said. "We've never really seen this before on a protoplanetary disk. Over time they've now separated and split into two shadows. They were so close to each other in the earlier observation they were missed. The best solution the team came up with is that there are two misaligned disks casting shadows. I was flummoxed at first, and all my collaborators were like: what is going on? We really had to scratch our heads and it took us a while to actually figure out an explanation." "When I first looked at the data, I thought something had gone wrong with the observation because it wasn't what I was expecting. "We found out that the shadow had done something completely different," said Debes, who is principal investigator and lead author of the study published in The Astrophysical Journal. John Debes of AURA/STScI for the European Space Agency at the Space Telescope Science Institute in Baltimore, Maryland, compared the TW Hydrae disk to Hubble observations made several years ago. The second shadow was discovered in observations obtained on June 6, 2021, as part of a multi-year program designed to track the shadows in circumstellar disks. Because the TW Hydrae system is tilted nearly face-on to our view from Earth, it is an optimum target for getting a bull's-eye-view of a planetary construction yard. In its infancy, our solar system may have resembled the TW Hydrae system, some 4.6 billion years ago. TW Hydrae is less than 10 million years old and resides about 200 light-years away. The two disks are likely evidence of a pair of planets under construction. This could be from yet another disk nestled inside the system. Now, a second shadow – playing a game of peek-a-boo – has emerged in just a few years between observations stored in Hubble's MAST archive. ![]() One explanation is that an unseen planet's gravity is pulling dust and gas into the planet's inclined orbit. The shadow isn't from a planet, but from an inner disk slightly inclined relative to the much larger outer disk – causing it to cast a shadow. In 2017, astronomers reported discovering a shadow sweeping across the face of a vast pancake-shaped gas-and-dust disk surrounding the red dwarf star. ![]() Newswise - The young star TW Hydrae is playing "shadow puppets" with scientists observing it with NASA's Hubble Space Telescope. Artificial color, to enhance details, has been added.įOR RELEASE: 10:00 a.m. This is a visible-light photo taken with the Space Telescope Imaging Spectrograph. This makes them slightly inclined to each other. They are evidence for two unseen planets that have pulled dust into their orbits. The shadows rotate around the star at different rates like the hands on a clock. The original inner disk is marked in this later view. The picture on the left shows a second shadow that emerged from yet another nested disk at the 7:00 o’clock position, as photographed in 2021. This shadow is cast by an inner disk that is slightly inclined to the outer disk and so blocks starlight. The left image, taken in 2016, shows just one shadow at the 11:00 o'clock position. The disks are tilted face-on to Earth and so give astronomers a bird's-eye view of what's happening around the star. Credit: IMAGE: NASA, ESA, STScI, John Debes (AURA/STScI for ESA) IMAGE PROCESSING: Joseph DePasquale (STScI)Ĭomparison images from the Hubble Space Telescope, taken several years apart, have uncovered two eerie shadows moving counterclockwise across a gas-and-dust disk encircling the young star TW Hydrae. ![]()
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