Dying White Dwarf Stars Can Explode Like Nuclear Bombs, Study Says

Dying White Dwarf Stars Can Explode Like Nuclear Bombs, Study Says
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Did you know that star death and nuclear weapons have something in common?

A new study found that when a white star explodes as a supernova, it can detonate similarly to a nuclear weapon on Earth, LiveScience reports.

White dwarfs are dim, fading, Earth-sized cores of dead stars that are left behind after regular-sized stars have depleted their fuel and shed their outer layers.

Our sun will once turn into a White Dwarf and over 90% of the stars in our galaxy.

Past research discovered that white dwarfs could also die in nuclear explosions officially known as type la supernovas.

Little is known about what starts the explosions, but past work suggested that it may occur when a white dwarf gets some extra fuel from a binary companion, maybe thanks to a collision.

Type II supernovas, in contrast, happen when a single star dies and collapses in on itself.

Researchers suggested a new mechanism that may define how type la supernovas – a white dwarf can detonate like a nuclear weapon.

As a white dwarf cools down, uranium and other heavy radioactive elements called actinides crystallize inside its core.

On some occasions, the atoms of those elements spontaneously experience nuclear fission, thus splitting into minuscule fragments.

The instances of radioactive decay release vast amounts of energy and subatomic particles called neutrons, which can also break up nearby atoms in a chain reaction.

If the quantity of actinides inside a white dwarf’s core goes past a certain mass threshold, an explosive, runaway nuclear fission may happen.

The outburst can then provoke nuclear fusion, with atom nuclei fusing together to produce immense amounts of energy.

In a similar mechanism, a hydrogen bomb relies on a nuclear fission chain reaction to detonate a nuclear fusion explosion.

The new study’s determinations and computer simulations revealed that a critical mass of uranium could indeed crystalize from the mixture of elements typically found in cooling a white dwarf.

If the uranium explodes due to a nuclear fission chain reaction, the scientists discovered that the produced heat and pressure in the white dwarf’s core might be high enough to produce the fusion of lighter elements like oxygen and carbon-producing a supernova.

Charles Horowitz, the study’s co-author and astrophysicist at Indiana University, stated in an interview with Space.com:

“The conditions to build and set off an atomic bomb seemed very difficult — I was surprised that these conditions might be satisfied in a natural way inside a very dense white dwarf. If true, this provides a very new way to think about thermonuclear supernovae and perhaps other astrophysical explosions.”

Horowitz believes that the newly discovered mechanism makes up for half of explaining how and why type la supernovas happen.

The new findings may help explain type la supernovas that occur within a billion years of a white dwarf’s formation, as their uranium hasn’t completely radioactively decayed/

Horowitz said that when it comes to older white dwarfs, type la supernovas can happen through mergers of two white dwarfs.

Future research may resort to running computer simulations to pin down whether fission chain reactions in white dwarfs can provoke fusion and how that happens.

“There are many different physical processes going on during the explosion, and therefore there are many possible uncertainties,” Horowitz added.

The work may also reveal new means of detecting whether or not the newly found mechanism is the reason why some type la supernovas happen.


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