Many thousands light-years away, at the very outskirts of our Milky Way Galaxy, researchers have discovered something no one’s ever seen before - a two star system (two stars circling a common center of mass) that’s moving so fast, it’s clocked speeds that nearly match the escape velocity of our galaxy. And this is, according to our current physics, unexplainable. According to astronomer, something must be assisting this star system produce such unbelievable momentum, and until now, the best explanation we had for hyper-velocity stars is that they were being pushed by the supermassive black holes that exist in the center of a typical galaxy. But the scenario with this star system is quite different: this binary star is nowhere near a supermassive black hole.
Titled PB3877, and sited nearly 18,000 light-years away from Planet Earth, this binary star system is not the first hyper-velocity star we’ve discovered in our galaxy. Astronomers have so far detected over 20 hyper-velocity stars that appear hell-bent on getting out of our cosmic neighborhood.
One of those hyper-velocity star is US 708, which was discovered in 2005 to be crashing through the Milky Way at almost 745 miles per second (that's 1,198 km per second, or 2.7 million miles per hour) - fast enough to outcome the gravitational pull of the galaxy. At that speed one could easily travel from Earth to the Moon in just 5 minutes.
All the other Hyper-Velocity tars discovered were single star systems. This is the first time ever astronomers have discovered a double-star system that’s reached hyper-velocity speeds. Ulrich Heber, one of the researchers behind this discovery, from the Friedrich Alexander University in Germany, said:
"We studied hyper-velocity stars since 2005, the year of discovery of the first three. In the meantime about two dozen have been found, but all are single, none has a companion directly visible in its spectrum."
Another thing that make PB3877 different from all the other hyper-velocity stars discovered so far is that all the other hyper-velocity satrs discovered ere near the supermassive black holes at the center of the galaxy.
Astronomers first identified PB3877 in 2011 by looking into data provided by Sloan Digital Sky-Survey (SDSS) and at that time it was considered to be a single star system.
With the recent observations made by the 10-metre Keck II telescope in Hawaii and the 8.2-metre Very Large Telescope (VLT) in Chile, astronomers in Germany was able to verify that it was both a hyper-velocity star, and a binary system.
According to current observation, it seems to consist of one super-hot star that's more than five times hotter than our Sun, and a second star that's 1,000 degrees cooler than our Sun.
Astronomer Thomas Kupfer from the California Institute of Technology, says:
"When we looked at the new data, much to our surprise, we found weak absorption lines that could not come from the hot star. The cool companion, just like the hot primary, shows a high radial velocity. Hence, the two stars form a binary system, which is the first hyper-velocity wide binary candidate."
Astronomers have presented a hypothesis that dark matter could be responsible for this but they are not certain yet.
The results have been issued in the Astrophysical Journal Letters, and according to the astronomers, the simple presence of this binary system puts pressure on known models and our current understanding of dark matter in the our Milky Way Galaxy. Well somebody needs to tell Stephen Hawking to get his interstellar spacecraft out there to give us a better explanation.