Astronomers have gotten closer to identifying the mysterious interstellar object.

Oumuamua is a mildly active comet which was discovered by Robert Weryk on 19^th October 2017. He made use of the Pan-STARRS telescope, located at the Haleakala Observatory in Hawaii, to detect this first-ever object from beyond our solar system. At the time of this discovery, Oumuamua had already passed its closest point to the Sun and was moving away from it. Similarly, it was at a distance of 33,000,000 kilometers from the Earth. According to an estimate of astronomers, this surprise visitor traveled for billions of years before entering our solar system but the exact traveling time is unknown.

Oumuamua is a small object which resembles the objects of the outer Solar System due to its red color. Despite its close approach to the Sun, Oumuamua showed no signs of a comet tail. However, it is moving with non-gravitational acceleration which is consistent with comet outgassing. A significant rate of rotation signifies that it possesses a lot of high-density metal. The rapid pace of Oumuamua means that it cannot be captured in a solar orbit and will leave our solar system to continue its journey through interstellar space.

Ever since its discovery, astronomers were interested in finding the origin of Oumuamua and a recent report suggests that scientists have made a massive progress on this question. For long periods of time, they had no idea where this interstellar interloper came from but now, they have narrowed down its source to four stars. It is some achievement given the fact that there are 1.6 billion stars in total. Timo Prusti, the Project Scientist of Gaia at the European Space Agency (ESA), talked about the importance of this finding by saying,

“It is a very interesting object that immediately raises the question: Where does it come from? People have been trying to address this issue with existing data right from the beginning when it was discovered. But the quality of the available data wasn’t good enough to really find any candidates.”

The researchers used the data gathered in June for their research and found that Oumuamua wasn’t hurtling through space willy-nilly. Instead, it picked up some extra speed while moving near the Sun. This behavior is similar to comets and scientists believe that something like ice was turned into water vapors which propelled the object forward at a much faster pace than usual. As the astronomers caught the comet on its way out of our solar system, they had to retrace its path to find its origin.

For this reason, they consulted a huge set of data gathered by Gaia, the space telescope of the ESA. It allowed them to pinpoint the precise locations of the stars. The researching team used 22 months of data from the Gaia Mission to identify four small dwarf stars that could have produced Oumuamua. One of these dwarf stars is similar to our Sun and is known as HIP 3757. Another possible candidate is HD 292249 while the other two stars have no names as of yet.

The theory proposed in this research suggests that Oumuamua belongs to a star system with at least one gas giant planet. All these stars are planet-less for now but this can change anytime. The analysis of 34 months of data from Gaia is expected to be released in 2021 and it will reveal a lot of new stars which may produce new candidates for the comet’s home. Prusti mentioned that it may prove to be a good finding in the following words:

“What might be is that among the stars, we might get a better candidate, where the velocities — and also how close the encounter — are a better match than for these four stars. It might be that we get many more candidates, but one or two of them are really good candidates.”

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