Strange asteroids orbiting near Neptune. They can hide important information

However, to feel satisfied, it is worth noting the moons of Neptune first. So far, we know fourteen of them, of which the largest are definitely Triton and Nereid. Each of these two moons has very distinct characteristics. Triton orbits Neptune in the wrong direction, automatically indicating that it is in fact an object that did not originate near Neptune, but was simply captured from the Kuiper Belt. Moreover, it is the coldest planet in the entire solar system. Its average temperature is only 38 K above absolute zero. The Nereid, on the other hand, moves in such an elongated orbit that when it is farthest from the planet, it is actually seven times farther from it than when it is closer.

Neptune Trojan asteroids

The term Trojan asteroids is mainly associated with the Trojans of Jupiter. These are two groups of asteroids orbiting the sun in a very close orbit to Jupiter, with one group 60 degrees ahead of Jupiter in L4 (the so-called Greek camp) and the other 60 degrees behind Jupiter in L5 (the Trojan camp). Since the gravitational pull of the Sun and Jupiter balances out at L4 and L5, objects there can stay there for a very long time. In total – in the case of Jupiter – scientists have counted more than 12,000 Trojan horses.

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However, this does not change the fact that other planets in the solar system also have Trojan analogues. One of these planets is Neptune. So far, from the data updated in January 2023, 31 Neptune Trojans can be found in the catalog. It is possible that there are more of them, but very small objects (50-100 km in diameter) are very difficult to see from a distance of 4.5 billion km from Earth. Recently, scientists decided to take a closer look at them. Now, however, the results of these observations have been published.

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Although Neptune itself is associated with the color blue, the asteroids orbiting near it turn out to be … reddish, redder than any other asteroids we could find in the solar system. So far, astronomers have looked at only a few asteroids from this group, however, and it has required the use of the largest astronomical telescopes on Earth. Now finally Almost twice the sample. Telescopes at the Palomar Observatory, Gemini North and South, and the Keck Telescope were used for the observations. It can’t get better at the moment. All telescopes over the course of nearly two years have looked at the group of 18 Neptune Trojans.

The reddish color of all the observed objects indicates the presence of chemicals such as ammonia and methanol on the surface. These compounds are not found on asteroids near Jupiter or in the asteroid belt for one simple reason. Both ammonia and methanol in the form of ice turn into gas very quickly under the influence of solar radiation. The closer you are to the sun, the lower your chance of seeing it.

Scientists believe that the four reddest objects in the sample most likely formed far from the sun and only came close to it later and hit the gravitational tentacles of Neptune.

Neptune’s Trojan asteroids may be hiding important information

Astronomers point out that, due to their remoteness, the Neptunes have not changed as much under the influence of solar radiation over the ages as the asteroids closest to the Sun. Thus, they can be an excellent source of information about what asteroids looked like 4.5 billion years ago, right after the formation of the solar system. By comparing them to asteroids from our neighborhood, we will theoretically be able to detect how conditions have changed in the solar system over its history.