Predicting supernova explosions with advanced simulations
by Riko Seibo
Tokyo, Japan (SPX) Nov 21, 2024

A research team led by Wun-Yi Chen and Ke-Jung Chen at the Institute of Astronomy, Academia Sinica (ASIAA) has unveiled critical insights into the physics of supernova shockwaves through advanced computational simulations. Leveraging the high-performance Kawas computing cluster at ASIAA, the team spent over two years developing the world's first two-dimensional, multi-wavelength radiation-hydrodynamics simulations. Their work offers unprecedented accuracy in modeling photon transport and its impact on shockwave dynamics, allowing precise comparisons between simulated and observational data. The findings are published in the 'Astrophysical Journal'.

Massive stars, between 10 and 30 times the Sun's mass, undergo dramatic transformations at the end of their life cycles. An iron core collapse forms a neutron star, releasing immense gravitational energy as neutrinos. This triggers a shockwave that destroys the star. As the shockwave moves through the star and reaches its surface, photon energy diffuses forward, producing an intense and fleeting flash known as a "supernova shock breakout." Lasting only a few hours and dominated by X-rays and ultraviolet light, this flash is a precursor signal, potentially enabling predictions of supernova explosions.

The research team focused on supernova 1987A to study this phenomenon. Their simulations reveal that a star's environment significantly affects the shock breakout flash, providing insights into circumstellar conditions and mass loss preceding supernova events. Unlike one-dimensional models, their two-dimensional simulations highlight how fluid instabilities enhance the brightness and duration of the flash, reshaping our understanding of these precursor signals.

"The interaction between radiation precursors and the surrounding medium is crucial for forming the shock breakout signal. Our new multi-dimensional, multi-band simulations can more accurately describe the complex radiative fluid dynamics during shock breakout," said Wun-Yi Chen, first author of the study.

Dr. Masaomi Ono, a co-author at ASIAA, added: "This research clearly demonstrates that even for spherical explosions, the shock breakout signals derived from two-dimensional radiative fluid dynamics may differ from those predicted by one-dimensional models. Multi-dimensional radiative fluid dynamics is vital for assessing the shock breakout signals of core-collapse supernovae, especially in non-uniform circumstellar medium."

Dr. Ke-Jung Chen, leader of the research team, emphasized the future implications: "These simulations provide essential reference data for future observations and predictions of supernovae. Next-generation X-ray and ultraviolet space telescopes will capture more supernova shock breakout flashes, furthering our understanding of the early evolution of supernovae and the final evolution of massive stars."

Full caption:Shock breakout of hypernovae: Hypernovae are even more violent astronomical phenomena than supernovae, with explosion energies exceeding those of supernovae by more than ten times. These powerful explosions are typically accompanied by strong jets that create distinct shock breakout structures at the poles of the star. The jets not only drive the explosion but also induce intense fluid instabilities within the ejected material, further mixing the star's internal substances. Recent observational datas have suggested that the famous supernova 1987A may be closely related to a jet explosion, rather than exhibiting the spherical explosion predicted by previous one-dimensional models. Image Credit: ASIAA/ Ke-Jung Chen Research Report:Multidimensional Radiation Hydrodynamics Simulations of Supernova 1987A Shock Breakout

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