For more than 70 years, scientists have been predicting the existence of a particular object in the outer solar system. These potential bodies are small and are believed to be an important first step in the planet formation process.
These hypothetical objects have a radius of only 1 to 10 kilometers, making them difficult to spot from our location. Now astronomers believe they did.
Looking up at the sky for hours, they were given evidence of an object just 1.3 km in radius around Pluto's orbit. The find could ultimately be a representative of this proposed class of small, "kilometer-sized" objects of the Kuiper Belt.
Due to their small size and weakness, the objects can not be seen directly. For example, astronomers at the National Astronomical Observatory of Japan tried a different method ̵
They chose 2,000 stars and spent a total of 60 hours observing them with the help of two small 28-centimeter telescopes.
The work paid off – the team found evidence of a tiny body called planetesimal, orbiting the Sun at a distance of 32 astronomical units (AU). That's actually Pluto's orbital range, which is between 29 and 49 AU.
This is the first time that any of these planetesimals have been discovered, the researchers said – and it is a wonderful achievement, considering the distances and the tools used.
"This is a real win for small projects – our team had less than 0.3 percent of the budget of major international projects – we did not even have enough money to build a second dome to protect our second telescope. Nevertheless, we managed to make a discovery that is impossible for the big projects, "said NAOJ astronomer Ko Arimatsu.
We do not know exactly how planetary formation works, but according to the current hypotheses, it is something like this.
After a star is born, it is surrounded by a dust disk and gas swirled in its orbit. Electrostatic forces begin to bind together particles in this protoplanetary disk, forming a lump; As the lump gets bigger, its gravitational force also increases, causing more and more particles to accumulate, making the lump even bigger.
We have seen these discs around other stars with the help of radio astronomy and even a picture of what astronomers think of a forming planet.
Here, closer to our house, is the Kuiper Belt – a broad slice of rock and ice bodies beyond the orbit of Neptune – a remnant of our early solar system. It contains larger bodies, including dwarf planets such as Pluto (2,377 kilometers) and 2014 MU69 (31 kilometers).
Because they are protected by ice and far from solar radiation, these bodies are believed to be time capsules that sustain the conditions of the formation of the solar system. It is believed that these objects between 1 and 10 kilometers testify to the point between the initial electrostatic accumulation of dust and the frenzied growth of the snowball sector.
This discovery with relatively cheap telescopes on a roof in Japan means that this is likely. Planetsimals are more common than previously thought – a beautiful proof that our model of planetary formation is on the right track.
And the team is not done yet. They are targeting a far-fetched price.
"Now that we know that our system is working, we will examine the Edgeworth Kuiper Belt more closely," said Arimatsu. "In addition, we are targeting the still undiscovered Oort Cloud."
The team's research has been published in the journal Nature Astronomy .