A A race against time to coordinate an intergovernmental effort to move imaging equipment to a mountaintop in Chile's Atacama Desert sounds like something out of a spy thriller. But the reason for the rush was even more dramatic – the explosive death of a massive star and the rapidly closing window for observing it.
On April 10, 2024, astronomers discovered supernova SN 2024ggi just 22 light-years away, and Yi Yang, an assistant professor at Tsinghua University in China, quickly contacted the European Southern Observatory for permission to use their Very Large Telescope in Chile to image it. SN 2024ggi provided a rare opportunity to study a massive stellar explosion; if Ian had waited, the opportunity would have been lost. Fortunately, he made it in time.
The shape of the initial supernova explosions of massive stars, in this case a red supergiant that is 12 to 15 times more massive than our Sun, has been a matter of debate. As a star gains more mass over the course of its life, layers of mass envelopes form around its core, consisting of heavier and heavier elements that undergo nuclear fusion. When a star runs out of fuel, the massive shells collapse around the core, bounce off, and send shock waves outward. It was this initial “breakthrough phase” that Yang sought to capture.
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“The geometry of the supernova explosion provides fundamental information about the evolution of stars and the physical processes leading to these cosmic fireworks,” Yang said in his report. statement.
Astronomers have tried to model supernovae that result from the death of massive stars, but until now they have been unable to observe any of them directly. In the study published V Achievements of scienceYang and his team explained their findings. Using a technique called spectropolarimetry, they determined the shape of SN 2024ggi's explosion based on the polarization signature of the light it emitted. The team found that the initial explosion had an oval shape, similar to an olive, which smoothed out as it developed, spreading into space while maintaining its axis of symmetry.
This startling discovery promises to rewrite our understanding of stellar evolution. According to co-author Ferdinando Patata, it is also “a powerful reminder that curiosity, collaboration and quick action can unlock deep understanding of the physics that shapes our Universe.”
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Main image: ESO/L. Sidewalk
