One of the highlights of 2017 was the discovery of someone else's object, which climbed into our system. At first they thought it was a comet, then an asteroid, and now they are considered something interstellar. Hawaiian astronomers gave him the name Oumuamua, which translates as “the first messenger from afar, who arrived first.”
The analyzes have already helped to get a lot of important information about the rare cigar shape of the object and its composition (ice and carbon-rich surface). It also has an unusual orbit beyond our system, and a speed of 26 km / s. The Breakthrough program even auditioned him for the existence of intelligent life, suspecting that we have an alien ship. But no signals were found.
The last study focused on the place of arrival of the object. Most likely, he flew in from the neighboring “moving group of Pleiades”. It could simply be pushed and sent into interstellar space.
Based on the trajectory, we managed to simulate how the body traveled through the galaxy and compare it with the motion of nearby stars. It turns out that Oumuamua flew past 109 stars in the distance of 16 light years. Could come from five stars in a local association.
At the initial impetus, the object moved with sufficient speed to escape from the home planet or star. That is, at first the speed was small, which corresponds to a collision with five stars.
When was he kicked out of the house?
As a rule, the stars moving with average speed during formation gradually change tempo. When colliding with other objects (massive stars and molecular clouds) they are affected by gravity. Compared to the average motion of the rest of the Oumuamua galaxy, it moves slowly, and therefore has been in interstellar space for a long time.
The color of the surface hints that this is a relatively young object. Deprived of the protection of the magnetic field of the star, he had to be attacked by cosmic rays, interstellar dust and gas, which are gradually painted in the red surface layer. But Oumuamua's color is more neutral. That is, he received blows only from cosmic rays for hundreds of millions of years.
How was it thrown away?
Oumuamua is characterized by a very elongated shape and does not look like the celestial bodies we are used to. Most likely, it was created by a relatively high-energy process, such as a collision or ejection from an emerging star. Most objects in the outer part of the planetary system are represented by ice, and in the inner part - by stone. In Oumuamua, there is an equal combination of elements, so it could appear in the middle part of the system (like an asteroid belt). Perhaps Oumuamua was thrown out of a dense binary star system due to the powerful influence of gravity. But this is only the tip of the iceberg. Scientists assume that approximately 46 million such facilities pass through our system every year. Most are too far away, so they are not accessible to telescopes. But future devices will be able to obtain valuable information that will allow a better understanding of the mechanism for creating stars and planets.