Two “very red” rocks in the asteroid belt could come from beyond Neptune

Scientists have discovered two giant rocks in the asteroid belt between the orbits of Jupiter and Mars that shouldn’t be there.

The asteroids, called 203 Pompeja and 269 Justitia, look like transneptunian objects – those that lie beyond the eighth planet in our solar system.

Both have “complex organic matter” on their surface and are redder than any other object in the asteroid belt.

It is possible that they formed near Neptune at the start of the solar system’s life before being transplanted into the asteroid belt during a violent phase of “planetary migration”, experts reveal.

“This discovery therefore provides new evidence that planetesimals formed at the periphery of the solar system have moved towards the asteroid belt in Jupiter’s orbit,” JAXA, the Japanese space agency, said in a statement.

203 Pompeja is about 70 miles (110 km) in diameter, while 269 Justitia is 35 miles (55 km), according to JAXA.

203 Pompeja is the only “very red” asteroid known to date among some 250 bodies larger than 70 miles in diameter found in the asteroid belt, experts report.

Both were discovered in the 19th century, but their color was detected through visible and near-infrared spectroscopic observations from the Infrared Telescope Facility (IRTF) in Hawaii and the National University of Hawaii Astronomical Observatory. Seoul (SAO) in Korea.

In general, objects in the inner solar system tend to reflect more blue light because they do not contain complex organic compounds like carbon and methane.

Objects in the outer solar system – after Neptune – are redder because they contain a lot of these compounds, which are red in the visible and near infrared light wavelengths.

So the fact that both are redder than any other “D-type” body (which until now were considered the reddest objects in the asteroid belt) suggests that they originate from the outer solar system.

“To have this organic material, you first have to have a lot of ice on the surface,” study author Michaël Marsset of the Massachusetts Institute of Technology (MIT) told The New York Times.

“So they had to train in a very cold environment. Then the solar irradiation of the ice creates these complex organic compounds.

If asteroids were too close to the Sun, temperatures would not allow these ice sheets to exist, Marsset said.

In addition, the characteristics of 203 Pompeja and 269 Justitia support a known theory called the Nice model.

The theory – developed in the French city of the same name – is that when the giant planets first formed, they were closer to the Sun than they are today.

NASA explains: “The planets interacted with each other and with the surrounding small bodies and eventually experienced instability, in which Neptune, Uranus, and Saturn moved outward and Jupiter inward.”

This would theoretically have brought the two ultra-red asteroids from beyond Neptune into the asteroid belt over several million years.

Nice’s model also supports the idea that there was another Neptune-like planet that was thrown out of the solar system, commonly known as Planet Nine.

The new research was led by Sunao Hasegawa at JAXA and published in the Astrophysical Journal Letters.