Strange star system may hold first evidence of an ultra-rare 'dark matter star'

a black hole surrounded by a ring of white light

Astronomers long thought that a peculiar star system observed by the European Space Agency's Gaia satellite was a simple case of a star orbiting a black hole. 

But now, two astronomers are challenging that claim, finding that the evidence suggests something far stranger: Possibly, a never-before-seen type of star made of invisible dark matter. Their research, which has yet to be peer-reviewed, was published April 18 on the preprint server arXiv.