The nearest hyper-velocity star ever discovered has been spotted, traveling over one million miles per hour through the galaxy. This new finding may help astronomers and cosmologists unwrap the mysterious nature of dark matter.
Researchers from China and the University of Utah discovered the unusual object. Only about 20 hypervelocity stars are known to exist, and this newest member of the group is the second-brightest of all such objects.
Study of how hypervelocity stars travel may reveal secrets about dark matter, as well as the giant black hole that resides in the center of the Milky Way.
"We can't see the dark matter halo, but its gravity acts on the star. We gain insight from the star's trajectory and velocity, which are affected by gravity from different parts of our galaxy," Zheng Zheng, assistant professor of physics and astronomy and lead author of the study said.
Astronomers believe hypervelocity stars are lone stellar bodies that were once members of binary star systems. As they orbited too close to the black hole at the center of our galaxy, the mass of that body - four million times greater than the sun - ripped the air apart.
Astronomers accidentally discovered the star while conducting research with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) in China. That observatory is able to observe around 4,000 stars at a time, using its 13.1-foot mirror. The device is usually used to capture light spectra of the stars, which can reveal information about the composition of stars and their immediate environment.
When the star was found, the velocity at which it traveled relative to our solar system was measured at over 1.4 million miles per hour. When measured against the center of our galaxy, the star is traveling at 1.1 million miles an hour.
"If you're looking at a herd of cows, and one starts going 60 mph, that's telling you something important. You may not know at first what that is. But for hypervelocity stars, one of their mysteries is where they come from - and the massive black hole in our galaxy is implicated," Ben Bromley, from the University of Utah, stated in a university press release.
Astronomers believe ordinary matter makes up less than five percent of the substance of the Universe. Around 27 percent is composed of mysterious dark matter, which surrounds galaxies like a halo. Movement of the hypervelocity star through this halo may provide information on the phenomenon.
Discovery and study of the hypervelocity star was profiled in the Astrophysical Journal Letters.
