Astronomers Detect Explosion On A Hot Dead Star’s Surface

A team of astronomers was able to detect a powerful explosion from a unique type of star system. According to their study, the system is composed of dead and dying stars.

The study was conducted through observations carried out by various radio telescopes based on Earth. It was published in the journal Astronomy and Astrophysics.

The cosmic explosion, which was actually triggered by a burst of gamma rays, was first detected by NASA’s Fermi satellite in 2010. Through radio telescopes on Earth, astronomers were able to identify the source of the powerful outburst.

According to their observations, the explosion happened on a star system identified as V407 Cyg. The astronomers noted that V407 Cyg is a unique type of stellar system known as a symbiotic nova.

Symbiotic novae are rare types of systems because they contain a small white dwarf and a pulsating red giant. A white dwarf is the stellar core remnant of a Sun-like star that has reached the end of its life cycle. Red giants, on the other hand, are stars that have expanded as they reach the final stage of their lives.

According to the astronomers, the explosion was triggered by the contrasting combination of stars within V407 Cyg. As the system’s red giant expands, it emits a wind of material that accumulates on the surface of its companion white dwarf.

Eventually, the volume of the material on the white dwarf reached critical density, triggering a powerful outburst on the surface of the stellar core remnant.

Through the radio telescopes, the astronomers were able to capture images of the cosmic explosion within V407 Cyg. Images collected within a span of about 200 days showed the evolution of the explosion’s shockwave as it reached the atmosphere of the red giant.

“Novae, with their sudden increases in visible light emission, have fascinated astronomers for centuries and their revelation in gamma rays has been a great surprise,” Marcello Girolett of the National Institute of Astrophysics INAF in Italy, lead author of the study, said in a statement.

“Having been able to witness, thanks to radio waves, not only the increase in brightness, but also the choreography produced by the interaction of these two stars is a very exciting result, and one of great scientific value,” he added.