A red dwarf star commonly known as Scholz’s star has caught the attention of astronomers. It is almost imperceptible, according to the reports of the scientists.
An artist’s depiction of Scholz’s star. Photo credit: Michael Osadciw/ University of Rochester.
A team of astronomers have concluded from their studies that a red dwarf star passed at 0.8 light-years from our sun years ago, at the time when modern humans migrated to Asia. Unfortunately, our ancestors might not even have noticed the star though.
The red dwarf star has been nicknamed Scholz’s star and is officially known as WISE J072003.20-084651.2. It is described as being extremely faint as it was discovered only back in 2013 when it was only 20 light-years away. It is so inconspicuous to the human eyes that even when it was 25 times closer than this and hence 600 times brighter, it would not have been observed with the naked eye. Detecting it back then (when it was 0.8 light-years away) would have required binoculars which were not yet invented at that time.
However, Scholz’s star can flare since it is a magnetically active star. This enables it to be occasionally bright to attract attention.
Scholz’s star most probably passed through the region where most comets dwell, known as the Oort cloud. But, it is unlikely that it reached till the inner cloud from where it could have been propelled into the inner solar system. The event marking its close presence has been described as being “the closest known flyby of a star to the solar system” by Dr Eric Mamajek and his team in the Astrophysical Journal Letters.
Researchers have measured its radial velocity and concluded that it was moving away from the sun rather fast.
“Most stars this nearby show much larger tangential motion,” says Mamajek. “The small tangential motion and proximity initially indicated that the star was most 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.”