Where the ‘Oumuamua flew from? Potential stem stars have been located

Ever since astronomers spotted ‘Oumuamua, the first-ever object from outside the solar system, they have wondered where it came from. Using the latest and most precise star map, researchers have located four stars that could potentially be the object’s parent stars.

‘Oumuamua (named after the Hawaiian term for the „first messenger arriving from afar”) was spotted last October 19 by Rob Weryk, an astronomer working on a network of telescopes located in HawaiióIn the Pan-STARRS (Panoramic Survey Telescope And Rapid Response System).

Further examination of the object revealed that it is about 400 meters longóIn length and strongly elongated shape, resembling a cigar. The astronomers also reported that it is dark red in color and about ten times longer than it is wider. It flew into our solar system from interstellar space at tremendous speed from a direction almost perpendicular to the plane of the orbits of the planets in our system. Its orbit indicated an origin in the vicinity of the constellation Lutnia.

At first, astronomers were not sure what they were dealing with. No cometary activity was observed, so the object was classified as an asteroid. But after a detailedóBy a thorough analysis of the data, they concluded that it was, however, a comet.

Determining position ‘Oumuamua against a background of stars, scientists noted that the subróChews in the wayób, którego cannot be explained by the gravitational influence of the Sun, planets and other important bodies of the solar system. Instead, they found that the object’s trajectory and acceleration can best be explained by gases ejected by the ‘Oumuamua. This process is characteristic of a comet, not asteroids, although a tail of gas and dust has never been observed, whichóry accompanies most comets. The loss of water vapor and other gasesów slightly changes the acceleration of the object. The change is so small that it could only be seen by the most advanced observational instruments.

Now, thanks to an extremely precise star map created from data from the Gaia satellite, researchers have reconstructed the object’s retrograde motion and were able to narrow down the search for the object’s parent system ‘Oumuamua to just four stars.

Comets are remnants from timeóIn the formation of the systemóin planetary and it is possible that ‘Oumuamua was ejected from its parent system, while the planets were still forming there. To find the object’s home, astronomers had to trace not only the interstellar trajectory of the comet over time, but also locate the stars które may have crossed its paths in the last few millionóin years.

For this purpose, the teamół astronomerów led by Coryn Bailer-Jones of the Institute of Astronomy of the im. Max Planck University in Heidelberg, Germany, analyzed data from the Gaia satellite, whichóre were published in April.

Gaia’s data contains accurate information on the position, distance and movement in the sky for more than a billion stars in our Galaxy. Importantly, the data set includes the radial velocities of the stars (for 7 millionów of them), that is, information about how fast they are moving toward us or away from us, which made it possible to fully reconstruct their trajectories.

The latest retrograde analysis of the stellar visitor’s trajectory points to four stars. All are dwarf stars with masses similar to or slightly smaller than our Sun – and have had their "close to" An encounter with an interstellar comet from one to seven millionów years ago. However, so far we have not noticed that theóhe ISS had planets or was part of a binary system. A giant planet or companion star would be the preferred mechanism for ejecting a small body far into interstellar space.

Two of these stars have already been named. This is HD 292249 and HIP 3757. The other two have been provisionally named by the teamół Bailer-Jones, as "home-3" i "home-4".

The closest to the path ‘Oumuamua was the star HIP 3757. The paths of the star and the wayward comet appeared at a distance of only twoóch light years apart about a million years ago. However, due to uncertainties in the calculations, it is possible that it is the home of interstellar comet.

In contrast, HD 292249 was close to the object 3.8 million years ago. In twoóch other cases, the trajectory of the object and the star may have intersected 1.1 and 6.3 million years ago. Astronomers stress, however, that further research is needed to determine the exact place of origin ‘Oumuamua.

Sourceóbackground: ESA, Science Alert, photo. ESA/Hubble, NASA, ESO, M. Kornmesser