The star named KIC 8462852, or Tabby's Star has baffled astronomers for over a century. Also known as Boyajian's Star, after the assistant professor of physics and astronomy at Louisiana State University, Tabetha Boyajian, who first discovered it.
The star sometimes dims in brightness for a few days or weeks, before returning to its original brightness.
Astronomers have been guessing what the reasons behind the dimmings could be, and have just added one more theory to the lineup: that the star is eating up an exomoon stolen from another planet.
Tabby's Star's details
Located over 1,000 light-years away, the star is 50% larger than our Sun, and 1,000 degrees hotter. So far, it's the only star of its kind.
Over the past century, Tabby's Star has been slowly dimming in brightness and has exhibited dimming anywhere between a few days to a few weeks at a time, before returning to its brighter luster.
Tabby’s Star - with its mysterious dips in light that still defy complete explanation - was thought to be unique among the stars in our galaxy.— Phil Plait (@BadAstronomer) September 16, 2019
But not any more.https://t.co/hF5uVYxM4J
Categorized as an F-type star, it should not be dimming in brightness.
So, astronomers have been scratching their heads figuring out what could be causing the dimming, with theories ranging from something blocking it, or simply space dust being in the way.
More recently, however, scientists from Columbia University have pointed at another theory: a thick ring of debris is growing and orbiting the star.
The findings of the Columbia University scientists, Brian Metzger, Miguel Martinez, and Nicholas Stone, were published recently in Monthly Notices of the Royal Astronomical Society.
According to the researchers, the debris is coming from an exomoon — a moon that used to orbit a planet outside our Solar System.
The star has stolen an exomoon
On top of the abovementioned debris, scientists believe that Tabby's Star has also stolen an exomoon from a nearby planet that no longer exists.
Due to the strong radiation from the star, it has stripped the exomoon's outer layer, which is made up of gas, ice, and rock. Other large particles are thrust into orbit, ending up in a dust disk surrounding the star.
This could be an explanation as to why the star keeps dimming and brightening again.
Researchers are looking for other stars with similar dimming behaviors, which may help figure out this enigma.