A new study reveals that mysterious repetitive explosions of radio waves emitted in random patterns could come from neutron stars that explode asteroids with magnetic winds moving at speed. close to the speed of light.
Rapid radio bursts, or FRBs, are high-intensity radio waves that can emit more energy in a few milliseconds than the sun for nearly a century. Scientists only discovered FRBs in 2007, and many people are still unaware of their origins because of their short existence.
Because fast radio bursts are rare and bright – they can be seen for millions or even billions of light years ̵1; researchers often assume they originated from cataclysmic events, such as flares or neutron stars collide. (Neutron stars are the corpses of stars that have died in catastrophic explosions known as supernovas; the gravitational force of these stellar ruins is strong enough to crush protons and electrons together to form neutrons.)
Related: Scientists discovered a strange ‘fast radio explosion’ from our Milky Way
The mystery of the rapid radio explosion deepened even more when scientists discovered the first repeating rapid radio explosion in 2016. When astronomers saw repeating patterns during celestial events They often think celestial mechanics could play a role – for example, a planet that completes orbit around its star, or a rapidly rotating neutron star known as a pulsar. can emit radio waves from its magnetic poles, flashing like a beacon when viewed from the Earth’s perspective.
But the radio explosions during the 2016 event were, strangely, random in timing.
Asteroids and neutron stars
Now, the researchers propose that asteroids orbiting neutron stars could help explain at least some repetitive fast radio bursts, even those of random timing. The key to this concept is that the strong winds of particles normally blow out not only from living stars like our own sun but also from dead stars, such as pulsars. Why the pulses are so magnetic their wind is so, and why the pulses rotate so quickly, completing hundreds of revolutions per second, their wind can emit at a relative speed – that is, close to the speed light degree.
Scientists have calculated that an object orbiting a pulsar – perhaps an asteroid – will produce a wake in the surrounding star’s wind. The researchers calculated that an electric current would circulate around this waking zone, and as the surrounding star’s wind passed through this waking zone, the resulting magnetic field disturbances would produce a very narrow beam of radio waves. and very strong.
Researchers note that asteroids 0.6-6 miles wide (1-10 km) orbiting their pulsar at an astronomical unit (AU) or closer will produce rapid radio explosions. of magnitude detected so far, especially if the pulsars have strong magnetic fields. (One AU is the average distance between the earth and the sun, which is about 93 million miles or 150 million kilometers.)
Asteroids passing through the pulsar’s superfast, highly magnetic winds will continuously produce intense beams of radio waves, the scientists noted. But astronomers on Earth will only consider these beams to be explosions, in the rare cases when neutron stars, asteroids, and telescopes on Earth accidentally line up.
Study lead author Fabrice Mottez, an astrophysicist at the French National Center for Scientific Research and the Paris Observatory, told Space.com: “The short duration of radio explosions is due to timing. short that we observe in radio waves. .
Facing wind magnets
The researchers also discovered what repeatable fast radio explosions can look like when created by asteroids flying through the highly magnetic, relatively high winds of magnets, a type Rare neutron stars are the most powerful magnets in the universe. They found that asteroids around magnets can produce radio explosions about a thousand times faster than the strongest asteroid ever seen.
If this explanation is correct, the random patterns in repeating fast radio bursts are likely due to an asteroid cluster interfering with the wind of a neutron star, the scientists note, not is a rock. “In our model, there are several hundred asteroids, each with its own separate beam,” Mottez said. A moon-filled exoplanet around a pulsar or magneto could also explain this phenomenon, the researchers noted.
Mottez said gravitational interactions between asteroids in a colony could lead to anomalies in their orbits, leading to the time heterogeneity of any explosions that astronomers emit. Now, Mottez says.
In addition, the magnetic fields of the surrounding wind and the magnet wind will fluctuate frequently over time with the rotation speed of these neutron stars, thus affecting the direction of the radio beam from any orbiting object. , potentially making the time look more random, he added. Another cause of randomness, perhaps most important, would be wind turbulence, he said.
The scientists detailed their findings in an article accepted October 7 by the journal Astronomy and Astrophysics, also published on the print server arXiv.org.
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