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The Atacama Large Millimeter/submillimeter Array (ALMA) has captured the motion of spirals of dust around a young star and shown that the winding motion of the spiral pattern is conducive to planet formation. This provides new evidence for planet formation around this young star. The results could have implications for other young stars as well.

The findings are in the journal Nature Astronomy.

Observations have revealed a spiral pattern in the disk of gas and dust around the young star IM Lup located 515 light-years away in the direction of the constellation Lupus.

Spiral patterns are thought to be one of the signs that a new planet will form soon, but other things, such as an already formed planet, can also form spirals. These different types of spirals cannot be distinguished by visual inspection, but they are expected to move differently over time.

To determine the origin of the spirals around IM Lup, an international research team led by Tomohiro Yoshida, a graduate student at The Graduate University for Advanced Studies, SOKENDAI and the National Astronomical Observatory of Japan (NAOJ), created a stop-motion animation of the spiral pattern using four observations taken by ALMA over the course of seven years.

The motion of the spirals in the stop-motion animation shows that they were not caused by an already formed planet, and instead, the spirals might be helping to form a new planet.

Yoshida says, "When I saw the outcome of the analysis —the dynamic visualization of the spiral in motion— I screamed with excitement. This achievement was made possible by the long-term, stable operations of the ALMA telescope, which demonstrates the world's highest performance.

"In the future, we plan to conduct similar observations on other protoplanetary disks to create a documentary of the entire planetary system formation process."