In fact, it should not exist at all: only the 14th Neptune moon, found in 2016, has few circles within the 4,000-fold satellite Proteus path. Why it has not been invented and destroyed, now researchers have discovered. Accordingly, the small moon of Hippocampus from the rubble began to have a huge impact on Proteus – and it could have been destroyed several times and replenished, as scientists report in the "Nature" magazine.
The Neptune has pictures of a rich history behind them. Already in the early days of the solar system, the ice planet and the place swapped with a neighbor's uterus and caused injecting in the Kuiper belt. A little later, he held the Kuipergürtel object of 2700-kilometer – this is the largest Neptunmond Triton. However, most of the original Neptun photographs were destroyed, new satellite dishes were discovered, including the small shelters, Naiad, Thalassa, Despina, Galatea and Larissa.
© NASA / ESA, A. Feild (STScI)
New moon from Neptune
However, in 2016, another representative of the inner Neptune lakes was discovered: In images of the Hubble Space Telescope, astronomers had discovered a place of collapse light that circulated Neptun just inside Proteus. The object that was baptized S / 2004 N 1 was too small and far away to find out more.
Now, Mark Showalter of the SETI Foundation in California and colleagues has used new observation data and a modern way of processing images to learn more about the new moon discovered. Using algorithm, a number of images of the Hubble Space Telescope led so that the moon and its orbit could be apparent despite the limited exposure time.
At the same time, researchers now suggest Hippocamp as a new name for S / 2004 N 1 – after "sea horse" of Greek mythology.
The result: Hippocamp is the smallest moon of Neptune – its diameter is only 34 kilometers. The incredible thing, however, is its orbit: The creature is just 12,000-kilometer circles within Proteus – an object with a size of about 4,000 times its size and about 1,000 times the mass. "One would not expect to find such a small moon next to Neptune's largest internal moon," said Showalter.
The reason: The seriousness of the great Proteus would have long been to attract and destroy the small hippocampus. Instead, the calculations showed that the little Trabant was even closer to his great neighbor in the past. However, because Proteus falls out a little faster than Hippocampus, their distance has increased, as researchers report.
© Mark R. Showalter / SETI Foundation
After making of Proteus rubbish
But how does this strange behavior explain? A sign of this provides a Pharos crater on Proteus – an impact basin that possesses almost half the moon diameter. "This crater is unusual in terms of moon size. That could indicate that Proteus is rarely destroying this effect," said Showalter and colleagues. They suspect that this cosmic collision has spread a large amount of rock rubble several billion years ago – and so maybe "raw material" for the small hippocampus.
"Some of these debris could have accumulated in a fixed orbit of about 1,000 to 2,000 kilometers within the Proteus," said researchers. Some of these pieces rose to Hippocamp. This could explain the proximity of both fields, the Pharos crater and the small size of Hippocampus. If this situation is confirmed, Hippocampus would be a "child" Proteus.
Hippocampus like cosmic "Lazarus"
But that did not finish the stunning history of Hippocamp. As a result of the small moon's orbit, researchers come to the conclusion that he, as his inner neighbors, is repeatedly beaten by a lunch comedy over time, but he & # 39 ; It has been constantly rebuilt of the rubble – as in small Lazarus. The researchers estimate that Hippocampus could be "resurrected" nine times in the past four billion years.
"Based on estimates of the comet population in this area, we know that other huts of the external solar system are also hit by comets and then collapse," said co-author Jack Lissauer from NASA Ames Research Center. (Natur, 2019; doi: 10.1038 / s41586-019-0909-9)
Source: NASA, SETI Foundation