‘Runaway stars’ are streaking through the Milky Way at barely imaginable speeds, hurled by the force of vast cosmic explosions.
The stars are going so fast they will leave our galaxy – and researchers also believe our universe could be visited by alien stars from other galaxies.
A study highlighted the two fastest runaway stars discovered among six hypervelocity white dwarf stars.
Type 1a supernovae happen when two stars orbit one another, one of which is a white dwarf.
In a type 1a supernova, the white dwarf accretes matter from another star until the core of the white dwarf reaches a point where a runaway reaction triggers a thermonuclear explosion.
The superfast supernovae are thought to be hurled by an even more spectacular subset of type 1a supernovas, a D6 star – where a second detonation is triggered, known as a “dynamically driven double-degenerate double-detonation” scenario.
Scientists Discover Two of the Fastest Ever Recorded
Stars hurled by a D6 explosion go faster than 1,000 kilometres per second – fast enough to escape the Milky Way and fly into intergalactic space, according to Science Alert.
The stars were found thanks to data from the Gaia mission, a project by the European Space Agency (ESA) dedicated to creating a detailed 3D map of our galaxy.
Scientists used Gaia data to find four hypervelocity stars believed to have come from D6 scenarios – meaning that there should be many more out there.
The researchers believe there may be hypervelocity stars from other galaxies in our Milky Way.
They write: “If a significant fraction of type 1a supernovae produce a D6 star, the galaxy has likely launched more than 10 million into intergalactic space.
“An interesting corollary is that there should be large numbers of faint, nearby D6 stars launched from galaxies throughout the local volume passing through the solar neighbourhood.”
According to a new study, the speediest stars speed through the Milky Way galaxy are runaways from a small neighbouring galaxy.
Unveiling the Two Fastest ‘Runaway Stars’ in History
Scientists said that around 10,000 of these so-cry “hypervelocity” stars in the Milky Way were natural in a small satellite galaxy called the Large Magellanic Cloud. Each of that suns was once half of a dual-star system in which two stars orbit one another. But volatile breakups sent the stars flying away so fast that they escaped the gravitational pull of their home galaxy and travelled off into the Milky Way, the scrutiny suggests.
Work data from the Sloan Digital Sky Survey and monitoring from the University of Cambridge in the United Kingdom created computer simulations of these swift intergalactic stars, demonstrating how the boom of one star in a dual can send the other downright speedy enough to be ejected from the Large Magellanic Cloud.
Only about 20 such stars have been noticed directly within the Milky Way, but researchers said they suspect thousands more have yet to be found. Previously, astronomers thought that these hurry stars were on their way out of the Milky Way after confronting the supermassive black hole at the centre of this galaxy, which has a strong enough gravitational pull to ballista an orbiting star far, far away at incredible speeds. And one such intergalactic hypervelocity star seems to have been ejected by a hit explosion, according to an older study.
Two Fastest ‘Runaway Stars’ Ever Found
“Earlier explanations for the start of hypervelocity stars did not please me,” Douglas Boubert, a doctoral tutee at the University of Cambridge’s Institute of Astronomy and guide author of the study, said in a statement. “The hypervelocity stars are mostly established in the Leo and Sextans constellations, [and] we wondered why that is the case.”
The researchers suggested that the movement of the Large Magellanic Cloud (LMC) explains the positions of these stars. Despite its name, the LMC is much smaller than the Milky Way, which it orbits at about 900,000 mph (1,440,000 km/h).
“These stars have just leapt from an express train — no wonder they’re fast,” co-author Rob Izzard, a Rutherford male at the Institute of Astronomy, said in the statement. “This also describes their position in the sky because the speedy runaways are ejected along the orbit of the LMC regarding the constellations of Leo and Sextans.”
Not only have thousands of these fast runaway stars escaped the LMC to join the Milky Way, but there are probably about a million other runaway neutron stars and even black holes flung into the Milky Way, the researchers said.
