The space rock is 1.3km in diameter, a critical size in the path from dust disc to planetary system. Credit: Ko Arimatsu


The missing link of planetary evolution has been discovered for the first time – and it was found using off-the-shelf telescopes, set up on top of a local school.

The new find could help to confirm theories of planetary evolution dating back over 70 years which predict that the rocks of the early Solar System grew slowly to kilometre sizes, before rapidly merging together to form the planets.

However, if this is the case then there should be several kilometre sized objects left in the Kuiper Belt (also known as the Edgeworth-Kuiper Belt) – the region of icy objects left over from the formation of the planets which lies on the outskirts of the Solar System.

Until now, no one had found any in this size range, and so to hunt them down, a team from the National Astronomical Observatory of Japan created the Organized Autotelescopes for Serendipitous Event Survey (OASES).

The project searched for the rocks by looking for occultations, where a Solar System object passes in front of a star, temporarily blocking out the light.

With only a tiny budget to work with, the team monitored around 2,000 stars for 60 hours, using two 28cm telescopes mounted on top of the Miyako open-air school on Miyako Island, Japan.

After analysing the data, the team found one of their stars had indeed been occulted by a Kuiper Belt object 1.3km in radius.

“This is a real victory for little projects,” says Ko Arimatsu from the National Astronomical Observatory in Japan, who led the study.

“Our team had less than 0.3% of the budget of large international projects.

We didn’t even have enough money to build a second dome to protect our second telescope!

Yet we still managed to make a discovery that is impossible for the big projects.”

To find a kilometre sized object during such a small survey suggests that there are many objects like this in the region, supporting the theory that objects this size were an important aspect of planetary growth.

The next task will be finding more of them.

“Now that we know our system works, we will investigate the Edgeworth-Kuiper Belt in more detail,” says Arimatsu.


“We also have our sights set on the still undiscovered Oort Cloud beyond that.”