The Voyager twin probes NASA continue to make discoveries in interstellar space.
The Voyager mission has detected a new type of “electron burst,” which will provide insight into the mechanisms of star flaring, a new study reports.
Bursts occur when electrons from cosmic rays – particles moving rapidly from far beyond the solar system – are pushed by shock waves generated by solar flares. The electrons then accelerate further along the lines of the cosmic magnetic field at incredible speed, study team members said.
“The idea that shock waves accelerate particles is not new,” said corresponding author Don Gurnett, professor emeritus of physics and astronomy at the University of Iowa, in a statement. ” [But] we detected it in a new domain: the interstellar medium, which is very different from that of the solar wind, where similar processes have been observed. ”
The two Voyager spacecraft are still performing strong after 43 years in space, each regularly returning science to Earth from their remaining operating instruments. (Voyager 2 flew incommunicado for several months in 2020 due to planned repairs and upgrades to its radio facility here on Earth, but reconnected in November.)
The first step in creating electron bursts occurs with coronal mass ejections. These solar flares project huge amounts of super hot plasma into space and create shock waves that travel outward through the solar system.
These shock waves accelerate fast-moving cosmic electrons, charged particles that are likely from distant supernovas. Cosmic rays are further accelerated along magnetic field lines between stars in the interstellar medium.
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Eventually, the magnetic field lines propel cosmic rays at almost the speed of light – nearly 670 times faster than the solar shock waves that first pushed them. (The shock waves travel at around 1 million mph, or 1.6 million km / h, study team members said.)
“Physicists believe that these electrons in the interstellar medium are reflected by a strengthened magnetic field at the edge of the shock wave, and then accelerated by the motion of the shock wave,” the University of Iowa said. in the same press release. “The reflected electrons then coil along interstellar magnetic field lines, gaining speed as the distance between them and the shock increases. “
Voyager 1 and Voyager 2 both detected the electron bursts within days of their acceleration, and a little later the two probes spotted slower, lower-energy plasma wave oscillations through the medium. interstellar generated by bursts of electrons.
The twin spacecraft also detected the original solar shock wave up to a year after the event occurred; the wait time has happened because the spaceships are so far from the sun. Voyager 1 is approximately 14.1 billion miles (22.7 billion km) from the sun, and Voyager 2 is approximately 11.7 billion miles (18.8 billion km) from our star. (The average Earth-Sun distance is about 93 million miles, or 150 million km.)
Astronomers hope to better understand how shock waves and cosmic radiation originate from torch stars. Solar explosions can generate radiation that poses risks to astronauts at the International Space Station or other destinations, such as the moon (where NASA hopes to land in 2024.) Particularly violent eruptions can also threaten orbiting satellites. around the Earth and planetary infrastructures like power lines.
The new study was published Wednesday, December 3 in The Astronomical Journal.
Follow Elizabeth Howell on Twitter @howellspace. Follow us on Twitter @Spacedotcom and on Facebook.
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