A new study has revealed that 13 hypervelocity stars that have been discovered may be alien in nature, having traveled to the Milky Way from other galaxies. Hypervelocity stars, which are the most rapidly moving stars in our galaxy and travel at several hundreds of millions of miles per hour, are not gravitationally bound to the Milky Way and do not orbit the center of our galaxy like the sun does. Not not only do some of these stars leave the Milky Way altogether and head out into intergalactic space, some of them also leave other galaxies and end up in ours, as new research shows.
According to Live Science, a new study by astronomers from Leiden University in the Netherlands has identified 13 hypervelocity stars that researchers have determined are most likely alien stars and not from our galaxy at all, as tracing them to the Milky Way was an impossible task. Thus, instead of trying to escape from our galaxy, these stars may have actually escaped from others to enters ours, breaking their way in.
“Rather than flying away from the Galactic center, most of the high velocity stars we spotted seem to be racing towards it. These could be stars from another galaxy, zooming right through the Milky Way,” astronomer Tommaso Marchetti from Leiden University explained.
Marchetti and other researchers discovered these 13 alien stars after sifting through data from the European Space Agency’s Gaia satellite and using the velocity and position data of 7 million stars in the Milky Way. After looking to find the stars that were moving the quickest, they noticed that there were 20 undocumented stars.
Seven of these stars were discovered to to be “hyper-runaways” that had come from the galactic disc of the Milky Way and were now heading out fast in the direction of intergalactic space. However, the remaining 13 of the hypervelocity stars were moving on a path which demonstrated that it was very unlikely that they had originated from the Milky Way’s galactic disc. Instead, researchers believe that these are very likely alien stars that originally came from a neighboring galaxy like the Large Magellanic Cloud and eventually ended up here.
Elena Rossi, co-author of the new study, noted that while researchers are not quite certain yet how these 13 stars ended up going out of orbit in the first place, “Either way, studying them could tell us more about these kinds of processes in nearby galaxies.”
The new study which determined that 13 hypervelocity stars in the Milky Way are most likely alien stars from neighboring galaxies has been published in the Monthly Notices of the Royal Astronomical Society.