Washington, Oct 8 (IANS): Astronomers have discovered mysterious ripples moving at the speed of 10 km per second across a planet-forming disk -- providing valuable clues about how planets form inside these star-surrounding disks.

These never-before-seen features were seen within the dusty disk surrounding the young, nearby star AU Microscopii (AU Mic).

The fast-moving, wave-like structures are unlike anything ever observed, or even predicted in a circumstellar disk, researchers noted, who used NASA’s Hubble Space Telescope and the European Southern Observatory’s (ESO) Very Large Telescope in Chile for these findings.

“The images show a set of unexplained features in the disk which have an arc-like, or wave-like structure unlike anything that has ever been observed before,” said Anthony Boccaletti from Paris Observatory, the paper’s lead author.

AU Mic is located 32 light-years away in the southern constellation Microscopium.

It is an optimal star to observe because its circumstellar disk is tilted edge-on to our view from Earth.

The images reveal a train of wave-like arches, resembling ripples in water.

The researchers report that these ripples are moving -- and they are moving very fast.

“Because nothing like this has been observed or predicted in theory we can only hypothesize when it comes to what we are seeing and how it came about,” added team member Christian Thalmann of the Swiss Federal Institute of Technology in Zurich, Switzerland.

The ripples farther away from the star seem to be moving faster than those closer to it.

The results were published in the science journal Nature.