In their new study, scientists identified six stars in the Milky Way, along with two stars J0927 and J1235, traveling at 5.1 million miles per hour (2,285 kilometers per second) and 3.8 million miles per hour (1,694 kilometers per second). respectively.
The star J0927 has such a fast speed that it can travel from New York to Mississippi in a second.
The other four stars are slower. They travel at 2.2 million miles per hour (1,000 kilometers per second). They are fast enough to escape the gravitational influence of our galaxy.
„These stars are unusual because they travel much faster than normal stars in the Milky Way. Because they are faster than the galactic escape velocity, they are quickly ejected into intergalactic space,” said team leader and Harvard/Smithsonian Center for Astrophysics researcher Karim El-Badri. Space.com.
„We were looking for objects like this, so we had some hope and expectation that they would be there, but their properties were different than we expected.”
According to the team, the speed of the stars may be caused by a specific type of cosmic explosion called a Type Ia supernova – when a white dwarf – a dying star – receives more material from another star than it can handle.
As matter is donated to a white dwarf, it accumulates enough to start a thermonuclear explosion.
„They’re much hotter than ordinary stars – and their unusual formation history may have involved a supernova exploding right next to them!” said the astrophysicist.
According to the researcher in the journal Open Astrophysics JournalThe team thinks that an „even more violent and powerful supernova” might be needed to accelerate these stars to hypervelocities.
„The composition of runaway stars is very unusual,” explained El Badri.
„All the stars in the Milky Way have atmospheres made mostly of hydrogen and helium, but these materials contain neither hydrogen nor helium and consist mostly of carbon and oxygen.”
This indicates that the runaway stars are degenerate white dwarfs and further supports the idea that they are exploded at extreme speeds by D⁶ supernovae.
According to space reporter Michael Starr, „When that companion star is enveloped in helium gas by another white dwarf, something somewhat special, a D6 supernova occurs. Scientific alert.
„D6 is called a double explosion because it involves two separate explosions. The first explosion starts when one of the white dwarf stars accumulates too much helium gas, triggering a thermonuclear explosion,” Starr reported.
The researchers concluded that there is a significant population of these high-velocity stars running through the universe that astronomers have yet to discover.
Of course, turnover is fair game, and researchers believe that other galaxies are throwing high-velocity stars at us, just as our galaxy has blasted high-velocity stars at its neighbors.