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Recently specialists from NASA conducted in-depth study of asteroids, doing libration in the vicinity of their Lagrange points, near Jupiter. They are traditionally referred to as "Trojan" and "the Greeks". The results were interesting: first, scientists have discovered more asteroids than expected, and secondly, defined their composition.
In its time the planets of the Solar system were named by the names of the great gods, but small bodies, that is, asteroids, also caught the ancient names. On the orbit of Jupiter has long called their names legendary warriors of the Trojan war, described in the poem by Homer "Iliad". In accordance with historical acts they are divided into two groups: "Trojan" and "the Greeks".
To distinguish them simply - "the Greeks" always run ahead of Jupiter, and "users" catching up. Localized these groups of asteroids in the so-called triangular Lagrange points jupiterians orbit: this is the point L4 (around her focus asteroids with the names of the Greek heroes) and point L5 (she gathered defenders of Troy). However, there is one "but", namely: the legendary heroes Hector and Patroclus was not in their camps tradition with some delay, when the asteroid had already found the names.
Before you continue the story, I want to introduce you to the characters in this space "Iliad". So, "Achaean camp" ("Greeks") presents (588) Achilles (624) Hector, (659) Nestor, (911) Agamemnon, (1143) Odysseus, (1404) Ajax, (1437) Diomedes, (1583) Antilochos, (1647) Menelaus and other. For them it was noticed long ago that these "toropygin" ahead of Jupiter at 60 degrees.
In no less glorious "Trojan camp" hit (617) Patroclus, (884) Priam (1172) enej (1173) of Antip, (1208) Troilus and others. They are lucky much less than their rivals. They are doomed forever to be at 60 degrees behind Jupiter. However, presents a list of the hero is far from complete. According to data for October 2010, the scientists were opened 1733 "Trojan horse ' point L5 and 2793 "Greek" L4. As you can see, "the Achaeans" still in the lead, and not only in the race around the father of the gods, but in the number.
It should be noted that now Trojan" called all the asteroids that are in the vicinity of the Lagrange points L4 and L5 specific planet with such a feature. Relatively "their" planets such asteroids are located in the acute angles of the diamond: two of them are libration points L4 and L5, and the other two angles are the centers of gravity of the Sun and planets, and connects the short diagonal of this diamond. However, Jupiter, as befits the King of the gods, is the most densely populated population heroes-asteroids, although there are some in Neptune, Mars, and even the Earth. Their origin dates back to the resonance effects in a dynamic system.
And recently, NASA has made in-depth study of these asteroids making libration in the vicinity of their Lagrange points, according to an infrared space telescope's Wide-field Infrared Survey Explorer (WISE). The results of this research were very interesting. First, discovered more asteroids than was previously known, and secondly, defined their composition.
"With the exact values of the diameters and surface albedo 1 750 "Trojan" Jupiter, we have increased appreciably our knowledge about these two groups of asteroids ("Trojan" and "the Greeks"), " says Thomas Grew from the Institute of planetology (Arizona, USA). - With this information we were able to more accurately than ever, confirm that in the main cloud them on 40% more, than was considered".
With a telescope WISE scientists compared the color of asteroids both groups. It turned out that almost all "Trojan" consist of dark reddish rocks with low reflectivity. It is known that previously this question was actively discussed because of albedo main mass "Trojan" Jupiter depend on assessment of their total number (called the numbers up to a million) and weight (up to 20% of the mass of the asteroid belt).
If their albedo little, faithful should be considered as the upper estimate of their number and weight. Apparently, recent results speak about it, say astronomers, new data in color and albedo investigated WISE "Trojan" evidence in favor of this review. This is a drastic difference of the investigated objects from the asteroid main belt located between Mars and Jupiter, and small bodies related to the Kuiper belt beyond the orbit of Neptune. So we can say that the new results of observations not only did not remove the problems of the past, but rather added questions!
Maroon color asteroids in both groups at points L4 and L5 Lagrangian is primary and says, most likely, similar origin. "We have not seen any infrared asteroids, typical for the main zone and the population of the Kuiper belt, " commented Mr. Grew. - Instead, we found mainly homogeneous population of what we call asteroids D-type, maroon in colour, and among others - rather grey-blue S-and P-types".
The different types of asteroids is now the main discussed issue. In the asteroid belt are conducted thorough research. The distant objects of the Kuiper belt have another team because of weak beyond the orbit of Neptune, the solar radiation is not able to sublimate their surface ice.
But, characteristically, "the Trojans" Jupiter deprived of surface ice. But in orbit, the largest planet of the Solar system, the moon, most likely, would not have coped with the surface ice, if they were covered asteroids. The color difference jupiterians "Trojan" and "the Greeks" also speaks of the absence of their relationship with the main belt asteroids.
Asteroid matter is considered the oldest "building blocks" in the Solar system. "More research is needed to explore this unique oldest material" - says the scientist. As experts from NASA suggested that nowhere else in the Solar system is not seen such objects, which would be similar to "Trojan" and "the Greeks", it is possible that they are "autochthons" asteroid - born simultaneously with Jupiter in its orbit, the current of the species found in this area approximately 4.5 billion years ago!
Of course, this proposal is not the only possible explanation; in the Solar system many "lost" objects (like the same theis), and to attribute jupiterians "Trojan" it is possible not only to natives. Still, scientists say, if this theory is true, Trojans deserve send to them probe for the study of the chemical composition and structure. Their material is one of the most interesting research in the Solar system.