The flash of the radio star next
Discovered for the first time in 2007, the fast radio bursts (FRB, Fast radio bursts) continue to conceal their origin. These sudden flashes last only a few milliseconds and the characteristics of the radio pulses suggest that their place of origin is in very remote galaxies billions of light years away. New research, published in the Monthly Notices of the Royal Astronomical Society, suggests instead that the origin of the FRB will be much closer: the stellar flares in our own galaxy.
“In our opinion, the radio bursts are not as exotic as astronomers have believed from the beginning,” summarizes Avi Loeb of the Harvard- Smithsonian Center for Astrophysics, who led the research along with colleagues at the University of Tel Aviv.
The radio bursts are fast transient phenomena that give off a lot of energy in a short time. Only six FRB have been discovered so far, all in archive data, and each of these was observed once. Detailed analysis of the FRB have established that these radio pulses must be passed through a large column of electrons – electrically charged gas – on their way to Earth . If it were scattered electrons in intergalactic space, then the initial events that have produced the FRB should be very energetic and very distant, like the collapse of a neutron star into a black hole.
Loeb and colleagues reasoned instead on what events neighbors, and therefore much less energy, could make the same phenomenon originated detected. According to the researchers, the answer is the glow (flares) stellar. The electrons in the plasma of the stellar crown densely packed would cause the same effect on the impulse radio dispersion of the extremely more rarefied intergalactic plasma.
Astronomers know that there are only two types of stars that burst into “eruptions” that give rise to radio emission: young low-mass stars and binary “contact”stars. These are pairs of stars with a mass comparable to that of the Sun, orbiting so close together to share their outer gaseous layer. Both of these types of stars show fluctuations of brightness even in visible light.
To test their theory, the researchers of the group of Loeb have been searching for these types of variable stars in the vicinity of the area of the sky where it were located three of the known FRB. Using telescopes of the Wise Observatory in Israel, they found that one of the three areas examined is a contact binary system, a pair of Sun-like stars, located at about 2,600 light years from Earth, orbiting around an outdoor other every 7.8 hours. According to their calculations, it is quite unlikely that this is a mere coincidence.
“Every time we, astronomers find a new class of objects, we begin to discuss whether they are near or far,” said Loeb, using the example of gamma-ray bursts (GRBs, gamma ray bursts), initially thought to come from the Milky Way and only later reported at cosmological distances. “In this case we have exactly the opposite,” says Loeb. The lightning quick radio, as assumed so far away, may actually originate from rare and powerful stellar eruptions in the circumscribed area of our galaxy.