Astronomers Uncover Uncommon White Dwarf Duo Destined for a Spectacular Supernova Explosion

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The event will be ten times brighter than our Moon in the night sky, but never fear, it won’t happen for another 23 billion years

Margherita Bassi – Daily Correspondent

The cosmos holds many wonders, and recent findings by astronomers have illuminated the presence of a unique pair of white dwarfs that are destined to eventually explode in a supernova. Published in a study in the journal Nature Astronomy, this discovery could redefine our understanding of stellar evolution in our galactic neighborhood.

White dwarfs are the remnants left behind after stars exhaust their nuclear fuel. When two of these dense stars exist in close proximity, the one with the greater mass can draw material from its companion. This process may lead to a Type Ia supernova when the accumulating mass exceeds a specific threshold, often theorized to occur in binary systems of white dwarfs.

Notably, this remarkable discovery represents the first identification of a binary system capable of producing a Type Ia supernova, located merely 150 light-years from Earth. Such a distance is relatively close within astronomical terms, prompting lead researcher James Munday from the University of Warwick to speculate that more such systems may exist within our vicinity, waiting to be uncovered.

Munday expressed excitement over the find, stating, “For years, we have been on the lookout for a significant binary of white dwarfs, so discovering one with such a high mass near Earth was exhilarating.” The analysis showed that these white dwarfs are notably close together, only 1/60th of the distance between the Earth and the Sun, with a combined mass of 1.56 times that of our Sun, a factor that underscores their eventual demise.

The two white dwarfs, comparable in size to the Earth, exhibit different diameters, one being about 20% larger and the other 50% larger, indicating their extraordinary density—akin to compressing the mass of the Sun into a volume the size of Earth. According to study co-author, astrophysicist Ingrid Pelisoli, these stars likely began as significantly more massive entities, with initial masses estimated to be three to four times that of the Sun.

As these dwarfs orbit one another—a process currently taking over 14 hours per cycle—they will gradually spiral closer, eventually reducing their orbital period to mere seconds. The resulting interaction will lead one dwarf to siphon off material from the other, triggering a complex chain reaction that results in a Type Ia supernova characterized by multiple explosive events.

The first explosion will occur as the growing white dwarf surpasses the mass limit for stability, followed by a core explosion, where ejected material from this event will impact the companion white dwarf, instigating a similar reaction. The anticipated explosion will be immensely powerful, estimated to be “a thousand trillion trillion times” the energy of the most potent nuclear weapon, lasting approximately four seconds.

Researchers anticipate that the repercussions of this double detonation will obliterate both stars just prior to their merger. When it occurs, this supernova will shine ten times brighter than the Moon as seen from Earth. Such consistent brightness in Type Ia supernovae makes them indispensable “standard candles” for astronomers, enabling measurements of vast distances within the universe.

Despite the closeness of this system, there is no cause for alarm regarding its future explosion, as scientists project it will happen in roughly 23 billion years. For context, the Earth is around 4.5 billion years old, and the universe itself is approximately 13.7 billion years old. By the time this event unfolds, it’s plausible that the Earth—and even the Sun—may no longer exist as we currently understand them.

“Even so,” notes writer Stephen Luntz for IFL Science, “perhaps some extraterrestrial beings on a distant planet will witness the majestic spectacle that this supernova will provide.”

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