Astronomers from Ohio State University at Columbus have found that the sun emits large amounts of high-energy gamma rays, and this occurs during the period of minimum activity. According to scientists, it has something to do with magnetic fields, but the exact mechanism is still unknown. This is reported by Science News.
High-energy gamma rays are not created directly by the Sun, but arise as a result of the interaction of cosmic rays with protons in the solar matter. Usually gamma radiation is absorbed by a star, but the presence of strong magnetic fields alters the trajectories of cosmic rays, and high-energy photons are emitted into outer space.
Researchers analyzed data from 10-year observations (from August 2008 to November 2017) conducted by NASA's Fermi Gamma-ray Space Telescope. The period of low solar activity fell on the period 2008-2009, and the high one - in 2013. Scientists have estimated the number of gamma radiation emitting events, as well as the energy of photons, depending on the activity of the Sun.
The researchers found that the sun is emitting more gamma rays with an energy of 50 billion electron volts (50 GeV) than predicted. Moreover, beams with an energy of 100 GeV were recorded, while they appeared at low solar activity. So, one of the photons had an energy of 467.7 GeV. In addition, since the Sun is bombarded by cosmic rays from all directions, one would expect that gamma photons are emitted by the star uniformly, but during the minimum activity, energetic photons were emitted by the equator, and during the maximum - mainly by the poles.
According to astronomers, this indicates an unusual behavior of the Sun's magnetic fields. Attempts to associate the excess of gamma rays with solar flares and sunspots have so far been unsuccessful. Scientists plan to continue research and measure the strength of magnetic fields using the Parker Solar Probe, which was launched on August 12, 2018.
