The first hypervelocity stars (HVS) have been discovered by scientists from Harvard-Smithsonian Center For Astrophysics almost a decade ago, in 2005. Since then many astronomers pursue the search for new HVS with aim to use the parameters of these stars to create new astrophysical models capable of explaining the behavior of supermassive black holes, particularly those which are located at the centers of galaxies, and the origins of HVS.

Researchers believe that hypervelocity stars originate from so-called three-body interactions between binary stars and supermassive black hole at the center of the galaxy. In essence, during such interaction one star from the binary system becomes bound to black hole, while its movement energy is transferred to the second member of the two-star system, and due to this transfer it literally gets “thrown” out of the galaxy. Term ‘hypervelocity’ means, that these celestial bodies exceed the regular stellar velocity limits: the typical speed of movement of HVS can reach 3-4 million kilometers per hour (approximately 1000km per second and above), while velocities of regular stars are at least ten times lower.

Research team including scientists from United States and Spain performed analysis of data obtained via Sloan Extension for Galactic Understanding and Exploration (SEGUE), project aimed to create a detailed 3D map of Milky Way galaxy. They were able to identify 13 new candidate hypervelocity stars, potentially exceeding the minimum escape speed from the galaxy with at least 90% probability (see a short definition of galaxy escape speed in video below). The paper detailing their research has been published at arXiv.org.