A Rare, Repeatedly Exploding Star Has Been Caught Producing Powerful Gamma Rays

The most energetic form of light in the Universe appears to be generated by a star that frequently explodes.

The analysis of an eruption from the system has shown that the shock wave expands into space and creates a particle that emits radiation. The conditions that generate this radiation may not be as extreme as previously thought.

It could be that bigger explosions, such as supernovae, are even more powerful particle accelerators, producing Cosmic rays with energies greater than a quadrillion electronvolts.

Ruslan Konno of the German Electron Synchrotron (DESY) in Germany and the HESS Collaboration said that the observation that the theoretical limit for particle acceleration can actually be reached in genuine cosmic shock waves has enormous implications for astrophysics.

It suggests that the acceleration process could be just as efficient in their more extreme relatives.

The star in question is a very special type of star. It is a recurrent nova, a type of star that is only found in the Milky Way, and it is located 4,566 light-years away. The object periodically erupts in an explosion called a nova, which goes off every 15 years or so, as you might be able to guess from the category name.

There is a cause of these eruptions.

A white dwarf is in close proximity to a red giant. As the two whirl around each other, material is sucked off the red giant by the smaller, denser white dwarf.

The hydrogen accumulates on the white dwarf's surface. A thermonuclear explosion occurs when the mass becomes so great that the pressure and temperature at the bottom of the layer is enough to cause it.

In August last year, the nova was so energetic that it temporarily became bright enough to see with the naked eye.

The stars forming the system are roughly the same distance from each other as the Earth and the Sun, according to Alison Mitchell, principal investigator of the HESS Nova program.

When the nova exploded in August 2021, the HESS telescopes allowed us to observe a galactic explosion in very-high-energy gamma rays for the first time.

The HESS array consists of five telescopes in Namibia and was recently upgraded with a new, highly sensitive camera. The light equivalent of a sonic boom is the radiation emitted when a gamma ray briefly travels faster than the phase velocity of light in the atmospheric medium.

Scientists can determine the energy of the rays that produced them. 100 billion electronvolts is the amount of electronvolts that the rays from the eruption of RS Ophiuchi had.

The mechanism that produces them in a nova has been revealed by the observations.

The team observed the nova evolve in real time. Their analysis shows that the white dwarf's nova slams into the red giant's wind, speeding up protons to very high energies, which can collide with each other to produce gamma rays.

This is the first time we have ever been able to do observations like this, and it will allow us to gain even more accurate future insights into how explosions work.

novae contribute to the ever-present sea of Cosmic rays and therefore have a considerable effect on the dynamics of their immediate surroundings.

The Cherenkov Telescope Array is 10 times more sensitive than current ground-based telescopes and should help scientists determine how common this process is in novas.

The research has been published.