Astronomers Finally Gain Evidence For The Existence Of The Much Hypothesized Planetesimals After Nearly 70 Years

Jan 29

Scientists have been hypothesizing for many years about how the existence of planets came by. A certain object in the Solar System has been thought to play a vital role, however, till date no solid evidence on the object was found. Astronomers had been working on this for about 70 years. Now finally, we have evidence on the existence of these planetary bodies or better known as the ‘planetesimals’.

Success of the occultation in gaining evidence of planetesimals

The astronomers knew that being where they are, it would be hard to view objects in space that were thought to be only between 1 to 10 kilometres in radius. This however, did not stop them from pursuing this road to obtaining evidence and they decided to go through with it by following a low budget process. The astronomers thus, lay watching the stars in wait for a body to pass by them and block their light, a method called ‘occultation’.

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After an observation of 60 hours of 2000 stars with two 11-inch telescopes, their hard work payed off and they were finally able to spot a body only 1.3 kilometres in radius! The planetesimal was orbiting the Sun at 32 AU which means that it is within the orbital range of the dwarf planet, Pluto.
Now that a solid evidence of these small bodies has been obtained, more hypotheses on planetary formation have come about. The current one starts with the birth of a star with dust and gas orbiting it. Then through electrostatic forces, these particles are bound together giving it a larger mass and thus a greater gravitational force.

The Edgeworth Kuiper Belt, consisting of rock and ice bodies, away from the Sun’s radiation is also a leading prospect of the idea that they are actually remnants of an earlier Solar System. It is said that if it weren’t for Neptune’s gravity affecting this particular region in space; these icy objects may have come together to form a planet.

Having achieved their first milestone with only exhausting 0.3 percent of the budget of big international projects, Ko Arimatsu, a NAOJ astronomer is keen on studying the Kuiper Belt more extensively and conducting more research on planetary formation. They also are more confident knowing that their system works and also wish to learn more about the still undiscovered Oort Cloud.

You can read more about this research in the journal Nature Astronomy.