A stone found in Egypt in 1996 could be the first evidence on Earth of an unusual supernova

The researcher Georgy Belyanin, in front of some monitors that show the images of backscattered electrons, which reflect the chemistry of the stone.

Therese van Wyck

One morning in December 1996, shortly after dawn prayer, the Egyptian geologist Aly Barakat found by chance in the desert that extends in the southwest of Egypt a peculiar carbonaceous and diamond-studded stone weighing about 30 grams.

At first, Barakat believed that it was a strange specimen of the so-called Libyan glass, an enigmatic type of yellow rock very common in this area of ​​the Sahara.

But he quickly suspected that he had in his hands an even more unusual object.

“I picked it up, but it wasn't a tektite [a natural glass object formed from terrestrial debris ejected by a meteorite impact].

”It was nothing known, so I kept it.

And from time to time he reviewed it to try to find out its nature, ”Barakat evokes to EL PAÍS.

"Contrary to what the researchers said at the time, I was sure that there were indications that a huge celestial body had impacted in that area, which caused the formation of the Libyan glass," he adds.

"Since it happened a long time ago, some 28 million years ago, its effects in the rocks of the region will not be easily found," he recalls thinking at the time.

In subsequent years, Barakat spent long periods of time studying the stone, though little support in Egypt and the limited resources at his disposal forced him to travel at his own expense to laboratories in South Africa in order to analyze the object.

It was then that the geologist discovered that the stone actually had an extraterrestrial origin.

And after publishing a book about it in 2012, he decided to pass the baton to other researchers.

In 2013, the group of scientists who took his witness confirmed that the enigmatic stone had an extraterrestrial origin, and later it was shown that it must have been part of a body several meters in diameter whose entry into the atmosphere must have been very bright.

Characteristics of chondrites were also found, a type of rocky meteorite that has not been modified with respect to the original object from which it came.

And it was because of its exceptional qualities that they decided to name it the Hypatia stone, in honor of the philosopher and scientist who lived in Alexandria at the time of the Roman Empire.

A 3 gram sample of the Hypatia stone.

Sebastian Carrasco (ROMANO SERRA)

Now, new analyzes of Hypatia developed in South Africa to better understand its origin have further expanded the interest surrounding the unique stone, confirming even more strongly that its pattern of concentration of chemical elements has not been observed before anywhere. natural, terrestrial or extraterrestrial object.

The researchers have also provided additional evidence that Hypatia formed before the solar system.

And for the first time, they have concluded that for now the process most likely to explain its origin is a supernova that is among the brightest events in the universe.

A hypothesis that, if confirmed, would make Hypatia the first evidence of this type of phenomenon that is known on Earth.

A supernova is the enormous explosion caused by some stars at the end of their lives.

The explosion that could have given birth to the Hypatia stone is a type Ia supernova, which could have occurred in a star system where two stars cohabit united by the force of gravity.

One of them is a white dwarf star.

The shiny gray-black Hypatia has a bimodal matrix, the first of which is almost devoid of elements heavier than oxygen, while the second has a more complex pattern.

In the study, published in

, researchers in South Africa have used very sensitive X-ray emission analyzes to obtain data from this second array for clues that might lead to its origin.

In total, the researchers detected 15 chemical elements, noting that the second matrix is ​​characterized, among other things, by its deficiency of silicon and manganese relative to its abundance of iron when compared to carbonaceous chondrites.

The stone also differs from less frequent meteorites, such as metallic and more primitive ones, formed during the early stages of the solar system, in that it contains a much higher proportion of carbon and its ratio of silicon and iron is different.

At a minimum, these results have allowed them to conclude that the kind of concentration pattern of chemical elements in Hypatia had not been observed before.

"The second matrix, in which we identified 15 [chemical] elements, is the main evidence that the stone is the result of a supernova explosion, because only based on the chemical [nature] of this matrix were we able to deduce it," explains Georgy Belyanin. , a geologist at the University of Johannesburg and co-author of the study.

With these pieces in hand, the researchers tried to complete the puzzle of how Hypatia was formed and how it reached the Egyptian desert.

Assuming that the stone was part of an object that at some point suffered an impact, as evidenced by its high abundance of microdiamonds, the possibility that this impact explained its peculiar concentration of chemical elements was considered.

But due to its composition, it could not come from the gas cloud where the solar system was formed, nor from the existing dust in interstellar space.

Instead, there was a more plausible option that could explain the anomaly in Hypatia's chemical composition: a supernova explosion.

Specifically, a type Ia supernova.

These chaotic phenomena result in the dispersion through the interstellar medium of the content of white dwarf stars and the products of the explosion, and are notable for predominantly releasing iron derivatives, which are also abundant in Hypatia.

Belyanin's team has established that the object Hypatia came from most likely originated outside the nebula that formed the solar system, but then entered it in its initial phase of formation and became trapped.

In this line, the fragments of a parent body formed, or present, in the solar nebula have a much higher probability of having later impacted one of its planets, like ours, than not objects from interstellar space.

“Even if it had entered [later], the chances of it colliding with Earth would have been very slim because of the different orbits.

If it entered the solar system after its formation, it would have become another body that flies around," Belyanin believes.

The researchers, however, point out that the enigmatic origin of Hypatia has not yet been closed, since there are six chemical elements in its matrix, two of which do not fit the type Ia supernova models.

This means that, if this is the case, the phenomenon that produced the stone would require a series of additional special conditions to close these gaps, something that will require further investigation to determine.

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