Oumuamua is a fascinating stone. The 400 meter long cigar shaped object is the first interstellar visitor ever to be found through our solar system. Although it was originally classified as an asteroid after its discovery, astronomers have now updated the label. "Oumuamua, it turns out, is indeed a comet, but unlike other known comets."
Oumuamua (then known as A / 2017 U1) was first discovered on 19 October 2017 by the Pan-STARRS 1 Telescope in Hawaii, and was originally thought to be an ordinary asteroid. It was not until their trajectory was plotted that the astronomers realized they were on a parabolic path, which meant they shot around the sun for a single lap before returning from our neighborhood forever.
Scientists from all over the world were enthusiastic about studying the object during his brief visit and we are still learning new things about it. Once the interstellar origin of Oumuamua was found, it was assumed to be a comet, as these are more likely to fly in space between the star systems. On closer examination, however, no signs of dust or gas were detected, suggesting that it was an asteroid. It was even scanned for signs of radio signals just to make sure it was not an alien probe.
A team of astronomers studied the object with Hubble until January 201
The revised label comes from measurements of its speed and position. The team calculated the trajectory it had expected on its way out of the solar system, based on the gravitational effects of the sun and planets like Jupiter. But & # 39; Oumuamua's observed trajectory was slightly different from that path.
"Unexpectedly, we found out that 'Oumuamua did not brake as fast as it should under gravity alone,' says Marco Micheli, lead author of the study.  Of course, another force was involved. The team investigated a number of possibilities, including radiation, heat or "solar wind" from the sun, a collision with another object, or the possibility that they are actually two separate closely connected objects, but none fits. There's only one real explanation left: "Oumuamua is a comet, and small dust and gas jets interfering with its orbit would clean the path it was watching, and although the astronomers could not directly recognize any of these signatures, the team says 'This may be because very little dust is released, or maybe it is mostly pure gas.' 'He has tested many possible alternatives, and the most plausible one is that' Oumuamua must be a comet, and that which emanate from its surface, causing tiny deviations in its trajectory, "says Davide Farnocchia, co-author of the study.
Although "Oumuamua is currently racing away from us at 114,000 km / h, astronomers now have a better idea of what to look for and how to examine these objects the next time they come in from interstellar space." You never know What kind of clues could bring them out of their home star system?
The research was published in the journal Nature .
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