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Juan Carlos López
Senior WriterAn engineer by training. A science and tech journalist by passion, vocation, and conviction. I've been writing professionally for over two decades, and I suspect I still have a long way to go. At Xataka, I write about many topics, but I mainly enjoy covering nuclear fusion, quantum physics, quantum computers, microprocessors, and TVs.
Alba Mora
WriterAn established tech journalist, I entered the world of consumer tech by chance in 2018. In my writing and translating career, I've also covered a diverse range of topics, including entertainment, travel, science, and the economy.
Identifying a supernova is an event that astronomers typically celebrate with enthusiasm. It’s no surprise, considering that it represents one of the most violent occurrences in the cosmos. Gaining a deeper understanding of supernovae is crucial. It helps scientists know more about the final stages of massive stars’ lives. They can also learn how the materials produced through stellar synthesis can give rise to new stellar systems.
Astrophysicists currently use mathematical tools to describe supernovae as the inevitable outcome of depleting the nuclear fusion processes in the cores of massive stars. During the main sequence stage, stars generate energy by fusing hydrogen nuclei. As this chemical element is consumed, the star begins to produce helium nuclei, leading to changes in its composition.
Throughout this process, an immense amount of energy is released, forcing the star to continually adjust itself to maintain hydrostatic equilibrium. This phenomenon results from the balance of two opposing forces. On one hand, gravitational contraction compresses the star’s matter. On the other hand, pressure from radiation and gases, which arises from the nuclear furnace’s ignition, attempts to make the star expand.
The Perfect Supernova
When a star is massive enough, it begins to deplete its helium reserves, producing new carbon nuclei while maintaining hydrostatic equilibrium. If the star continues to be massive enough, it won’t stop at carbon production. Once the core’s carbon is exhausted, the star will readjust itself by compressing and increasing its temperature, halting the gravitational collapse.
At this stage, carbon nuclei will ignite through nuclear fusion processes, leading to the creation of even heavier chemical elements. While carbon fusion occurs in the core, helium fusion takes place in the layer immediately above it. Hydrogen fusion occurs in the layer above that.
The iron core shrinks suddenly under the immense pressure from the layers of material above it.
During stellar nucleosynthesis, stars develop a layered structure reminiscent of an onion. The heaviest elements reside in the core, with lighter elements found in the layers above. If the star accumulates enough mass, there will come a time when the core is primarily composed of iron. This makes it impossible to obtain more energy from iron through nuclear fusion processes.
At that moment, the radiation and gas pressure aren’t enough to counteract the gravitational contraction. The iron core suddenly compresses under the enormous pressure exerted by the layers of material above it. The star has lost its hydrostatic equilibrium. As a result, all the matter that previously supported the core now collapses onto it at incredible speeds.
When this material finally reaches the surface of the nucleus, a rebound effect occurs. It ejects it with tremendous energy into the surrounding stellar medium, scattering it in the process. A supernova has just taken place. Some supernovae are so powerful that they emit more light in a few seconds than the entire galaxy that contains them. This phenomenon likely occurred with “Teleios,” a supernova remnant recently discovered by a team of astronomers at the University of Sydney.
The remnant is the material that remains dispersed in a region of space after a supernova explosion.
In the study of supernovae, the remnant typically appears as an expanding bubble. This bubble consists of a bright outer region where the shock wave is generated and a diffuse inner section made up of denser, cooler gas and dust. The image below accurately depicts a supernova, clearly illustrating the two regions.
Astronomers identified Teleios using the Australian Square Kilometre Array Pathfinder telescope. Notably, they observed something very intriguing: Its shape is almost perfectly circular. This symmetrical geometry is quite unusual for the material left over after a supernova explosion.
While researchers consider several scenarios that could explain this unique morphology, they suggest that further observations are needed to understand why Teleios is so different from other remnants.
Understanding the conditions that led to the formation of this cosmic object could help cosmologists gain insights into the processes that occur during a supernova. With this knowledge, they could also learn about the factors that influence the evolution of the remnant that remains in space long after the explosion. In fact, Australian astrophysicists estimate that Teleios is located between 7,170 and 25,100 light-years away from Earth.
Images | NASA Hubble Space Telescope | Xataka using DALL-E
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