The new, short but extremely intense image was captured by one of the most powerful X-ray machines in space. For the first time in history, it is called a new classic fireball. It confirms theoretical observations from more than 30 years ago.

The German-Russian telescope eROSITA observed the eruption of the Nova Volcano, located aboard the Spektr-RG Space Observatory at Lagrange Point L2 (where the James Webb Space Telescope is located).

New to the question is YZ Reticuli. It was discovered on July 15, 2020 and is located about 8,250 light-years away near the constellation of the Web. The analysis showed that the temporary brightening was the result of the so-called neoclassical – the outbreak of the white dwarf.

How is the new created?

White dwarfs are “dead” stars – collapsed cores up to eight times the mass of the Sun, which have shed their entire stellar atmosphere after nuclear fusion is complete. White dwarfs are small and dense – comparable to the size of the Earth, their mass is 1.4 times the mass of the Sun. This is called the Chandrasekhar boundary – if a white dwarf crosses it, it becomes so unstable that it explodes as a new one.

White dwarfs often occur in binaries with larger (albeit less massive) stars. If they are close to each other, a white dwarf can “suck” matter from its companion. Hydrogen accumulates mainly on the surface of the white dwarf, where it is heated. This contributes to reducing the mass of the dead star and speeds up the crossing of the Chandrasekhar boundary. A thermonuclear explosion is violent and throws excess matter into space. This is how new is made.

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On July 7, 2020, an extremely bright X-ray source appeared at a location later identified as YZ Reticuli and quickly disappeared. The observation was fully consistent with theoretical modeling of the nova fireball phase.

Predictions from 1990 posit that the short phase of a nova explosion fireball must occur between the decay of the rapid fusion that begins the explosion and the star’s brightening at optical wavelengths. This phase should appear as a soft, short, bright flash of X-rays, and recent observations support theoretical assumptions.

In a work published in temper nature You can read:

Due to the successful detection of the YZ Reticula flare by eROSITA, the presence of X-ray flashes was confirmed by observation. Our discovery also adds a missing piece to the measurement of the new moon’s total energy and completes the whole picture of photospheric evolution during a thermonuclear escape.