The most violent explosion in the universe… a star that completely disappears without leaving a trace sciences

Since the 1960s, astrophysicists have predicted an exceptional type of stellar explosion capable of completely obliterating a star without leaving behind a black hole or neutron star. For decades, this idea remained only a theoretical expectation, due to the rarity of these explosions and the impossibility of monitoring them directly.

But two recent studies have brought this scenario back to the forefront. The first provided the strongest indirect evidence of the existence of this rare type of supernova, and the second succeeded for the first time in photographing the true form of the explosion of a massive star during its first hours, giving scientists a new vision of the mechanisms of death of the largest stars in the universe.

The first study was published in the journal Nature and was led by Hui Tong, a doctoral student in astrophysics at Monash University in Australia, with the participation of Maya Fischbach from the Canadian Institute for Theoretical Astrophysics at the University of Toronto.

The second study was published in Science Advances and was led by Yi Yang from Tsinghua University in China, based on rapid observations using the Very Large Telescope of the European Southern Observatory.

When the explosion is too strong to leave residue

The life of most massive stars ends in a supernova explosion, usually leaving behind a neutron star or a black hole. But stars with a mass between 140 and 260 times the mass of the Sun may take a completely different path.

Hui Tong says: “Despite their enormous masses, these stars only live a few million years, that is, about a thousand times shorter than the life of the Sun, as if they were giant fireworks that burned quickly before exploding.”

Inside these stars, temperatures reach such extreme levels that they cause high-energy photons of light to turn into pairs of electrons and positrons, weakening the pressure that was resisting gravity. Then the star’s core suddenly collapses, and then a violent thermonuclear explosion explodes, completely tearing the star apart, leaving no compressed body left after it.

This phenomenon is known as a supernova resulting from the instability of pairs.

Where did the black holes disappear?

The study team looked at data from 153 pairs of black holes detected by gravitational waves, excluding black holes resulting from previous mergers.

The results showed a clear absence of black holes with masses ranging between 44 and 116 solar masses, a region that the researchers described as the “forbidden range.”

Maya Fishbach believes that the best explanation for this vacuum is that the stars that are supposed to produce black holes within this mass field completely destroy themselves before leaving any remains.

She said: “In most cases, massive stars produce black holes, but after exceeding a certain mass limit, physics imposes a different path, and no trace of the star remains.”

Although scientists have previously observed very bright explosions that may be candidates for this type, the current study represents the strongest indirect evidence to date.

The first picture of what the explosion looked like hours after it started

In a parallel achievement, an international team led by Yi Yang succeeded in directing the Very Large Telescope towards the supernova “2024ggi” (SN 2024ggi) only 26 hours after its discovery inside the galaxy “3621” (NGC 3621), located about 22 million light-years away.

This explosion is a classic example of the death of a red giant star with a mass between 12 and 15 times the mass of the Sun. Scientists used spectral polarization technology, which reveals the shape of the explosion even when the star appears to be just a point of light.

Dietrich Bade, an astronomer at the European Southern Observatory, said: “For only a few hours we could see the shape of the star and the explosion together, a stage that cannot be observed after one day.”

Measurements revealed that the ejected material initially emerged in the form of an olive-like shape, then became flatter as the explosion continued to expand, while maintaining a clear axis of symmetry.

The researchers believe that this result rules out some current models of star explosions, and supports other models that rely on the presence of a main explosion axis.

A new step towards understanding the death of stars

Scientists confirm that the combination of observing gravitational waves and direct observation of supernovae gives astrophysics unprecedented tools to understand the final stages of the life of giant stars.

“These results not only reshape our understanding of star explosions, but also show what rapid, cross-border scientific cooperation can achieve,” said Ferdinando Patat, an astronomer at the European Southern Observatory.

Researchers hope that future observatories will help find more of these rare explosions, and test theoretical models that have remained for decades without direct observational evidence.

Finally, when a star explodes, it not only announces the end of its life, but writes a new chapter in the story of the universe. Some stars are so great that they disappear completely, as if they were sacrificing themselves to give the universe new elements and deeper secrets.