Headline: Astronomers Map the Shape of a Supernova’s Breakout — and It’s Not Spherical
In a groundbreaking observation using the Very Large Telescope (VLT) in Chile, astronomers captured the very first moments of a massive star’s explosion. The result? The supernova’s “breakout” — the initial blast wave as it breaches the star’s surface — was elongated rather than perfectly spherical, overturning decades-old assumptions. Live Science+1
The event, designated SN 2024ggi, occurred when a star around 12–15 times the mass of our Sun ended its life. Just 26 hours after its first light was detected, VLT scientists trained their instruments and obtained data revealing the irregular, lumpy shape of the explosion front. Live Science+1
Why It Matters: Previously, supernova explosions — especially their initial breakout phase — were treated in models as roughly spherical. This finding forces astrophysicists to reconsider how stars explode, how energy disperses, and how element production is distributed in those first chaotic instants.
What’s Next: The scientific team hopes to catch future supernovae even earlier, enabling 3D mapping of explosion shapes. These insights may refine predictive supernova models and improve understanding of how heavy elements are dispersed across the cosmos.
At the beginning of the end of a star’s life, its core runs out of hydrogen to convert into helium. The energy produced by fusion creates pressure inside the star that balances gravity’s tendency to pull matter together, so the core starts to collapse. But squeezing the core also increases its temperature and pressure, making the star slowly puff up. However, the details of the late stages of the star’s death depend strongly on its mass.
A low-mass star’s atmosphere will keep expanding until it becomes a subgiant or giant star while fusion converts helium into carbon in the core. (This will be the fate of our Sun, in several billion years.) Some giants become unstable and pulsate, periodically inflating and ejecting some of their atmospheres. Eventually, all the star’s outer layers blow away, creating an expanding cloud of dust and gas called a planetary nebula.
All that’s left of the star is its core, now called a white dwarf, a roughly Earth-sized stellar cinder that gradually cools over billions of years.
A high-mass star goes further. Fusion converts carbon into heavier elements like oxygen, neon, and magnesium, which will become future fuel for the core. For the largest stars, this chain continues until silicon fuses into iron. These processes produce energy that keeps the core from collapsing, but each new fuel buys it less and less time. The whole process takes just a few million years. By the time silicon fuses into iron, the star runs out of fuel in a matter of days. The next step would be fusing iron into some heavier element but doing so requires energy instead of releasing it.
The star’s iron core collapses until forces between the nuclei push the brakes, then it rebounds. This change creates a shock wave that travels outward through the star. The result is a huge explosion called a supernova. The core survives as an incredibly dense remnant, either a neutron star or a black hole.
Material cast into the cosmos by supernovae and other stellar events will enrich future molecular clouds and become incorporated into the next generation of stars.
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Source: science.nasa.gov
