Milky Way kicks out 700 stars, discovered in intergalactic space
It seems our Milky Way galaxy doesn't want nearly 700 stars. A lot has to happen in order for a star to leave a galaxy, such as a meeting with a black hole. Scientists have discovered these rogue stars in intergalactic space.
reported in March of hypervelocity planets that hurtle throughout our galaxy 400 times faster than Earth. These runaway planets are able to fly around space at 30 million miles per hour (48 million kilometers), which is just a fraction of the speed of light.
The study was a successor to a study that concluded rogue stars do in fact exist. According to a press release
, a study by scientists in the United States has found approximately 700 of these runaway stars that were ejected from the Milky Way in intergalactic space.
Indeed, it is difficult to banish a star from a galaxy because it takes a very close encounter with a black hole at the galaxy’s core. In the past, astronomers have been able to locate 16 hypervelocity stars, but the stars are traveling so fast that it will eventually leave our gravitational grasp.
Vanderbilt astronomers are now working on another research project that identified 675 stars in the suburbs of our galaxy that were flung out from our galactic core. Much of these stars are red giants and maintain a high metallacity (measurement of chemical elements, excluding helium and hydrogen).
“We figured that these rogue stars must be there, outside the galaxy, but no one had ever looked for them. So we decided to give it a try,” said Kelly Holley-Bockelmann, an assistant professor at Vanderbilt, in the news release.
Most galaxies consist of a supermassive black hole at its center. Due to this galactic constitution, the gravitational field surrounding a black hole is so powerful that it can hasten stars to hypervelocities. One of the primary examples of these instances is a binary pair of stars that gets caught in the grip of a black hole and as one star becomes engulfed the other is shot out into the distance.
“Studying these rogue stars can provide us with new insights into the history and evolution of our home galaxy,” added Holley-Bockelmann, who said the study’s next step is to conclude if these stars are also red brown dwarfs rather than red giants.
The research findings were published in the May edition of the Astronomical Journal