In 1996, a rock from outer space was found in the Great Sand Sea in southwestern Egypt. The stone was strange even by alien standards. A team of researchers studying its chemistry now proposes that it came from a supernova — the brilliant, explosive collapse of a star.
The rock is called Hypatia, after an Egyptian mathematician from the 4th century. Based on the pattern of 15 elements in a 3-gram sample of the rock, a team of researchers suspects that Hypatia came from far beyond our stellar environment and emerged from the gas and dusty debris that followed the explosion of a distant star. Their research is published in the journal Icarus.
The researchers believe that Hypatia comes from a Type Ia supernova; these supernovas occur when white dwarfs (the small, dense remnants of stars) consume so much material, often from a neighboring star, that they explode. That distinguishes Typa Ia from Type II supernovas, in which the core of a large star collapses and causes a huge explosion.
“In a sense, we could say we ‘caught’ a supernova Ia explosion ‘red-handed’ because the gas atoms from the explosion were trapped in the surrounding dust cloud, which eventually formed Hypatia’s parent body,” said Jan Kramers, a geochemist at the University of Johannesburg, in a university release.
According to the publication, the mixing of gas atoms from the supernova and the dust in which the explosion occurred likely formed a bedrock around the early stages of our solar system billions of years ago. Entering and impacting the Earth, Hypatia’s parent rock shattered, creating the fragment found in 1996.
Kramers has been studying Hypatia for almost ten years. In 2013, argon isotopes from the rock confirmed Hypatia’s extraterrestrial origin, and follow-up studies in 2015 and 2018 indicated that Hypatia did not originate from any known comet,,, meteorite, or our solar system. Using a proton microprobe, the team inspected Hypatia’s elemental composition. They found that the elements of the rock indicated it didn’t even come from interstellar dust in our arm of the Milky Way.
Hypatia had too much iron to come from a Type II supernova or a red giant star. For example, the researchers suspected that the most likely explanation for Hypatia’s unique combination of silicon, sulfur, calcium, titanium, vanadium, chromium, manganese, iron, and nickel was a Type Ia supernova.
However, six elements were much more present than what models predict for something emanating from a Type Ia supernova: aluminum, phosphorus, chlorine, potassium, zinc, and copper. Kramers believes Hypatia may have inherited those elemental components from the red giant star that preceded the white dwarf that eventually exploded.
The new research was purely exploratory, and further isotope analysis of the elements in Hypatia will be needed to test the researchers’ hypothesis about the rock’s origin.
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Editor’s Note: The release dates in this article are based in the US but will be updated with local Australian dates as we learn more.