A light bulb that doesn't burn out but flares brighter and brighter until it blows the whole fixture apart. That's roughly how the most massive stars in the universe die. When a star's core heats up to billions of degrees, pairs of particles (electrons and their antimatter counterparts, positrons) begin to form. This process saps the energy that once held the star up, and it collapses, not quietly but in a monstrous thermonuclear explosion. Such an event is called a pair-instability supernova.
That's exactly the kind of blast that seems to have produced supernova 2023vbw. It erupted in a small galaxy where stars contain almost no heavy elements — an ideal place for such monsters. Telescopes tracked it for 190 days, and during that time it released ten times more energy than a typical core-collapse supernova. To pack that punch, the explosion must have hurled about 200–300 solar masses of material into space — a whole cloud of stellar matter.
But the most intriguing part isn't just the record-breaking brightness. The supernova's light revealed that the explosion wasn't perfectly spherical. The star's ejecta slammed into surrounding gas, and the shape of that collision exposed an asymmetry — perhaps the star shed its outer layers unevenly before dying. Such details will help us understand how giant stars live and die, the ones that once seeded the cosmos with the first heavy elements.
Right now we see only a handful of such flashes. But soon telescopes like the Vera Rubin Observatory will start finding them by the hundreds. Each one is a window into an era when the universe was young and full of stellar giants.
as written by the authors arXiv:2605.16487
Stars in the initial and carbon-oxygen core mass ranges of $$\sim140-260$$ and $$50-130$$ M$$_\odot$$, respectively, with low metallicity are predicted to experience copious electron-positron pair production in their cores, leading to a runaway thermonuclear explosion that obliterates the entire star in a luminous and long-duration pair-instability supernova explosion. Some previous supernovae have been interpreted in this context but lack the full range of predicted properties. Here, we report detailed observations and modeling of the hydrogen-rich supernova 2023vbw, which exploded in a low-metallicity ($$\sim0.1$$ Z$$_\odot$$) environment in a dwarf star-forming galaxy at a redshift of $$0.088$$. Its light curve exhibits a luminous ($$1.6\times10^{43}$$ erg s$$^{-1}$$) and long-duration ($$190$$ days) main peak, resulting in a total radiated energy of $$3\times10^{50}$$ erg, more than an order of magnitude greater than canonical core-collapse supernovae. Semi-analytical light-curve modeling yields a blue supergiant-like progenitor with an ejecta mass of $$170-350$$ M$$_\odot$$, radioactive nickel mass of $$1.2-1.6$$ M$$_\odot$$, and explosion energy of $$(6-13)\times10^{52}$$ erg, well matched by pair-instability models. The early and late-phase light curve and spectra also show evidence for interaction of the supernova ejecta with an aspherical circumstellar medium. Discoveries of numerous such events with the upcoming Rubin Observatory and Roman Space Telescope will shed light on the deaths of the most massive stars in the Universe.
The explosion of 2023vbw lasted longer than a probe's flight from Earth to Mars along the slowest trajectory.
In Isaac Asimov's novel 'The Gods Themselves', a star's explosion caused by a disruption in particle balance resembles the mechanism of pair instability.