(ORDO NEWS) — When Sicilian astronomer Giuseppe Piazzi spotted Ceres in 1801, he assumed it was a planet.
At that time, astronomers did not yet know about asteroids. Now we know that there are a huge number of them, they mainly live in the main asteroid belt between Mars and Jupiter.
Ceres has a diameter of about 1,000 km and makes up a third of the mass of the main asteroid belt. It is dwarfed in relation to most other bodies in the belt.
But what does a dwarf planet in the asteroid belt do?
Ceres did not form in the asteroid belt. It formed further in the solar system and then migrated to its current position. This is not the first study to come to this conclusion, but it adds weight to the idea.
(Note: Ceres has been called a dwarf planet, protoplanet, and sometimes an asteroid. It was officially classified as a dwarf planet in 2006.)
Ceres is one of three dwarf planets or protoplanets in the asteroid belt. The other two are Vesta and Pallas. The fourth major body, Hygiea, has a diameter of 434 km and may also be a dwarf planet. These four largest bodies make up half the mass of the asteroid belt.
The terminology and descriptions of the largest objects in the asteroid belt can be confusing, but Ceres stands apart from the other three.
She is the only body in the belt that is massive enough to maintain a spheroidal shape. It also has a transitional atmosphere called the exosphere.
Sunlight turns water ice and ammonia ice into steam, but the dwarf planet’s gravity is too weak to hold it. This is an important clue to the origin of Ceres, since asteroids do not normally emit steam.
The presence of ammonia is also a clue.
Comets contain volatile ices, such as ammonia, which are released when heated by the Sun. This is what creates the tail and coma of a comet.
“The presence of ammonia ice is strong evidence that Ceres could have formed in the coldest region of the solar system, at sufficiently low temperatures,” said Ribeiro de Souza, professor of physics at Sao Paulo State University in Brazil.
“Ceres began to form in orbit far beyond Saturn, where ammonia was abundant. At the stage of growth of the giant planet, it was drawn into the asteroid belt as a migrant from the outer solar system and lasted 4.5 billion years to the present day.
To test this idea, the team ran a large number of computer simulations. They modeled the formation of giant planets within the Sun’s protoplanetary disk, including Jupiter and Saturn.
They also included several embryonic planets that would have been precursors to Uranus and Neptune. They then added a group of objects similar in composition and size to Ceres.
“Our simulations showed that the formation stage of the giant planets was very turbulent, with huge collisions between the precursors of Uranus and Neptune, the ejection of planets from the solar system, and even the invasion of the inner region of planets with a mass greater than three times the mass of the Earth.
In addition, strong gravitational disturbance scattered objects similar to Ceres. Some of them could well reach the asteroid belt region and acquire stable orbits that can survive other events, ”said Ribeiro de Souza.
The team’s simulations also showed that Ceres is just one of many similar objects that existed at the dawn of the solar system. “Our main conclusion is that there were at least 3,600 Ceres-like objects beyond the orbit of Saturn in the past,” he said.
This study confirms previous findings and supports our understanding of how the solar system formed and evolved.
“Our scenario allowed us to confirm the quantity and explain the orbital and chemical properties of Ceres. The study confirms the accuracy of the most recent models of the formation of the solar system,” concluded Ribeiro de Souza.
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