Tuesday, April 20, 2021 08:45 AM (GMT + 7)
When a white dwarf explodes like a supernova, it can explode like nuclear weapons on Earth, a new study shows.
A shot of a white dwarf 10 years ago.
Earth-sized white dwarfs, which are left behind after medium-sized stars run out of fuel and flake off their outer layers.
One day, our sun will become a white dwarf star, as well as more than 90% of the stars in our galaxy.
Previous research has shown that white dwarfs can die in nuclear explosions known as type Ia supernovae. It’s not clear what caused these explosions, but previous studies suggest they could happen when a white dwarf takes more fuel from a binary companion, perhaps due to a collision. . (In contrast, Type II supernovae occur when a single star dies and collapses on its own.)
Now, researchers have proposed a new way in which type Ia supernovae could occur. It’s a white dwarf that explodes like a nuclear weapon.
When a white dwarf cools, uranium and other heavily radioactive elements called activators crystallize in its core. Sometimes the atoms of these elements go through nuclear fission spontaneously, splitting into smaller pieces.
These radioactive decay cases can release energy and subatomic particles, such as neutrons, can break down nearby atoms.
If the actinide count in the core of a white dwarf exceeds the critical mass, it could cause an explosive nuclear fission chain reaction. This explosion could then trigger nuclear fusion, with the atomic nuclei fusing to generate enormous amounts of energy. In a similar way, a hydrogen bomb uses a nuclear fission chain reaction to detonate, a nuclear fusion explosion.
The new study’s calculations and computer simulations show that a critical mass of uranium can actually crystallize from a mixture of elements commonly found in a cooling white dwarf star. If the uranium exploded as a result of a nuclear fission chain reaction, scientists found that the heat and pressure generated in the core of a white dwarf could be high enough to trigger the fusion of light elements. more, such as carbon and oxygen, form supernovae.
Specifically, these new findings could explain type Ia supernovae that occurred within a billion years after the formation of white dwarfs, because of their uranium. A type Ia supernova can occur through the fusion of two white dwarfs.
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