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& # 39; Oumuamua is a fascinating rock. The 400-meter-long cigar-shaped object is the first interstellar visitor ever detected across our solar system, and while it was originally classified as an asteroid after its discovery, the astronomers have now updated the etiquette. "Oumuamua, after all, is a comet, but it is unlike any other known comet.
Oumuamua (then known as A / 2017 U1) was first spotted on October 19, 2017 by the Pan-STARRS 1 telescope in Hawaii, and it was initially thought to be an asteroid commonplace. This is only when his trajectory was traced that astronomers realized that it was on a parabolic path, which meant that he was only one round around the Sun before to withdraw from our neighborhood forever.
Scientists around the world I studied the subject during his short visit, and we are still learning new things. Once its interstellar origins were established, Oumuamua was considered a comet, since these are more likely to move in the space between star systems. But on closer inspection, no sign of dust or gas was detected around him, suggesting that it was an asteroid. It was even scanned for radio signals, just to make sure it was not some kind of extraterrestrial probe.
A team of astronomers continued to study the object with Hubble until January 2018, when he became too weak. Using these data, researchers now say that "Oumuamua is a comet after all.
The revised label comes from measurements of its speed and position. The team calculated the expected trajectory of the solar system, based solely on the gravitational influences of the Sun and planets like Jupiter. But "the observed trajectory of Oumuamua differed slightly from this trajectory."
"Unexpectedly, we found that" Oumuamua did not slow down as fast as it should under gravitational forces alone, " explains Marco Micheli, lead author of the study. ] Clearly, another force was at stake. The team studied a range of possibilities, including radiation, heat or the "solar wind" of the Sun, a collision with another object, or the chance of that it is actually two very tight separate objects, but none of them. 19659005] This leaves only one true explanation: "Oumuamua is a comet. Small jets of dust and gas disturbing its orbit would perfectly explain the observed trajectory. Although astronomers could not directly detect any of these signatures from the object, the team says that this could be due to the fact that only a very small amount of dust is released, or can -being that it is mainly pure gas. has tested many possible alternatives and the most plausible is that "Oumuamua must be a comet, and that gases emanating from its surface cause tiny changes in its trajectory," says Davide Farnocchia, co-author of the study [19659007]. Oumuamua currently escapes us at 114,000 km / h, astronomers now have a better idea of what to look for and how to study these objects the next time we keep it away interstellar space. You never know what kind of clues they could bring us from their star system to the home.
The research was published in the journal Nature .
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