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The strange interstellar object that crossed our solar system in 2017 continues to amaze scientists
The visitor was named by astronomers Oumuamua "messenger from afar who arrives the first "in Hawaiian.
The elongated object was discovered in October last year by astronomers working on the Pan STARRS continuous sounding system at the University of Hawaii.
Oumuamua did not have the characteristic tail that defines comets and ] was originally clbadified as the first interstellar asteroid .
But the identity of the visitor has turned out to be much more complex.
"It must be a comet"
A team of astronomers led by M ark M icheli of the European Space Agency ( ESA), made high precision measurements using terrestrial instruments and the space telescope Hubble [194590] 14]
Micheli and his team discovered that the object deviated slightly from the trajectory that 39 he would follow if he was only affected by the gravity of the Sun and planets
"We unexpectedly discovered that Oumuamua was not slowing down as fast as it should. Gravitational forces, "said Micheli, lead author of the study published in the journal Nature [19459].
"We tested many plausible alternatives and [19659008] achievable is that Oumuamua must be a comet and the gases emanating from its surface cause small variations in its trajectory "said David Farnochhia of NASA's Jet Propulsion Laboratory. 19659003] Comets contain ice that changes from solid to gaseous when heated by the Sun, causing dust from the surface to create a diffuse atmosphere and sometimes a tail.
However the team It still has not detected dusty matter, so scientists believe that Oumuamua had to release only small amounts of dust
Comets vs.. asteroids
Comets and asteroids share common characteristics.
They follow unusual trajectories and are remnants of the materials that formed the Solar System.
The greatest difference is the material which composes them . While asteroids are composed of metals and rocks, comets are composed of ice, dust, rock and organic compounds.
For this reason, when comets approach the Sun, heat melts and vaporizes part of the ice. Comets or cometary hairs are clouds of gas or dust that surround the comet in a halo that expands as the sun forms the characteristic tail.
Unlike comets, asteroids normally ] have no tail since they remain solid even in the vicinity of the Sun.
However, some asteroids have been detected that acquire sporadic tails when they eject clouds of gas and dust after being hit by other asteroids.
Some scientists also believe that asteroids formed much closer to the Sun, where it was too hot for the ice to remain solid, while comets formed in a distance greater than the Sun which allowed them to remain frozen
Key Information
"Oumuamua is not the only case where the distinction between comets and asteroids does not exist. Was not clear, "says in statements to the BBC Sara Russell of the Natural History Museum of London.
"We find comet-like objects in the main asteroid belt", a region of the solar system included between the orbits of Mars and Jupiter.
Being the first visitor to another solar system, a comet can give us more information about the formation of the planets
"The comets probably formed in the outer regions of Other planetary systems, Russell explains: "Oumuamua and other interstellar travelers who finally visit our solar system can potentially give us great clues about the nature and composition of other planetary systems." can show us if our solar system is unique or one of the many habitable systems in our galaxy. "
Observations
Oumuama was observed by powerful ground telescopes and was last seen by Hubble at the beginning of 2018.
Astronomers will continue to badyze these observations, but we will never see Oumuama again.
In September, the comet pbaded near the Sun at ] a speed of 315,400 k ilometers per hour .
The comet is fast enough to escape the gravitational pull of the Sun and eventually will leave our solar system.
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