Repeatedly Exploding Stat Produces Gamma Ray, What Is Stellar Vampirism?

Researchers stumble upon a rare star that's seen to repeatedly explode while generating gamma-rays - the most energetic light form in the Universe.

The RS Ophiuchi binary system revealed that shock waves expanding into space acts as particle accelerators generating gamma radiation. The discovery suggests that conditions to generate the radiation don't need to be as extreme as scientists previously thought. In turn, it could mean that bigger space explosions, like supernovae, are more powerful particle accelerators that can produce cosmic rays with energies far greater than a quadrillion electronvolts.

Observations of Rare Repetitive Star Explosion Producing Gamma Radiation

Ruslan Konno, an astrophysicist from the German Electron Synchrotron, Germany, and the HESS Collaboration, explains that the theoretical limit of particle acceleration can be reached in genuine cosmic shock waves with significant implications in astrophysics. He adds that acceleration processes could be as efficient in much more extreme occurrences, like supernovae, reports ScienceAlert.

According to the study published in the journal Science, titled "Time-resolved hadronic particle acceleration in the recurrent nova RS Ophiuchi" The star in question, named RS Ophiuchi, is a unique binary star, located roughly 4,566 light-years from Earth, its a star type known as a recurrent nova, one in roughly only ten known in the Milky Way. The object periodically erupts in an explosion known as a nova and goes off roughly every 15 years.

Stellar Vampirism and How it Causes Repetitive Explosion of RS Ophiuchi

The cause for the unique periodic eruption is stellar vampirism. The binary system, RS Ophiuchi, consists of a red giant in close orbit with a white dwarf. As the two stars circumnavigate each other, material, such as hydrogen, is siphoned from the red giant by the denser, smaller white dwarf -- stellar vampirism.

The hydrogen then accumulates on the surface of the white dwarf, where it heats up. Periodically, the mass becomes too great that pressure and temperatures from the bottom layers are sufficient to trigger thermonuclear explosions - a nova, which violently expels excess material out into space.

The most recent explosion was observed in August of the previous year; it was so energetic that, momentarily, RS Ophiuchi could be seen with the naked eye.

Alison Mitchell from Friedrich-Alexander University, Germany, and a HESS Nova Program principal investigator explains that the stars forming the systems are roughly the same distance as Earth is to the Sun.

The HESS array in Namibia consists of five telescopes and recently was upgraded with highly sensitive cameras. The array can detect Cherenkov radiation when a high-energy gamma-ray strikes the atmosphere of Earth, producing a shower of supercharged particles. Since light travels slower in the air than in a vacuum, these particles momentarily travel faster than light, which creates a blue flash.

Observing how the nova explosion evolved in real-time, researchers reconstructed the gamma-rays producing phenomenon. According to the team's analysis, the shockwaves from the nova of the white dwarf slam into the red giant's wind, accelerating protons to high energies, collide with each other, producing gamma-ray photons.

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