Space

Alien Red Star Missed Hitting Our Solar System by Less Than a Light-Year

Catherine Griffin
First Posted: Feb 18, 2015 06:57 AM EST

An alien star may have nearly collided with our solar system. Scientists have discovered that 70,000 years ago, a star passed through the solar system's distant cloud of comets, the Oort Cloud. This makes it the only star to have approached so closely.

The star itself is nicknamed "Scholz's star." With its current trajectory, researchers estimate that it passed just 52,000 astronomical units away from our solar system, which is just .8 light-years. That's just 5 trillion miles. While this may seem far away, though, it's astronomically close; our closest neighbor star is Proxima Centauri, which is about 4.2 light-years away.

"Most stars this nearby show much larger tangential motion," said Eric Mamajek, one of the researchers, in a news release. "The small tangential motion and proximity initially indicated that the star was more likely either moving towards a future close encounter with the solar system, or it had 'recently' come close to the solar system and was moving away. Sure enough, the radial velocity measurements were consistent with it running away from the sun's vicinity-and we realized it must have had a close flyby in the past."

In order to actually chart the trajectory of Scholz's star, the researchers measured its spectrum and radial velocity through Doppler shift. Once the researchers pieced together the information, they found that the star was moving away from our solar system and that 70,000 years ago, it made its closest approach to our sun.

Currently, the star is about 20 light-years away. A small and dim red dwarf, it's now located in the constellation of Monoceros. And while it probably didn't make much of an impact on the Oort Cloud while it was nearby, it does show that these events do occur.

The findings are published in The Astrophysical Journal.

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