A stone found is the Egyptian desert formed within a supernova explosion outside of our solar system according to a paper published this week in the journal Icarus.
Called “Hypatia” after a female Egyptian astronomer, the stone was found in 1996 in the Great Sand Sea in southwest Egypt.
Now a three-gram sample has been determined to be utterly unlike anything in our solar system or even in the Milky Way.
It could be the first evidence on Earth of a supernova type Ia explosion, a particularly rare supernova—an exploding star that occurs in binary systems in which one of the stars is a white dwarf. They are some of the brightest events in the entire universe.
A group of chemists at the University of Johannesburg, South Africa has been forensically analysing the chunk of Hypatia since 2013.
Their hypothesis—and Hypatia’s timeline—goes like this:
- A red giant star inside a dust cloud collapsed into a white dwarf star.
- That white dwarf became part of a binary system with another star, which it eventually consumed.
- The white dwarf star then exploded as a supernova type Ia.
- The gas atoms from the explosion were caught in the dust cloud, which eventually formed Hypatia’s parent body.
- A big bubble of that gas and dust gradually became solid rock in the outer reaches of our solar system just as it was forming about 4.6 billion years ago.
- That rock hurtled towards Earth, striking the atmosphere and the desert and shattering.
“If this hypothesis is correct, the Hypatia stone would be the first tangible evidence on Earth of a supernova type Ia explosion,” said Jan Kramers at the University of Johannesburg. “Perhaps equally importantly it shows that an individual anomalous parcel of dust from outer space could actually be incorporated in the solar nebula that our solar system was formed from, without being fully mixed in.”
During their experiments Hypatia turned out to have only 1% of the silicon, chromium and manganese that it would have if it had formed within our inner solar system. It’s also got too much iron, sulphur, phosphorus, copper and vanadium. “We found a consistent pattern of trace element abundances that is completely different from anything in the solar system, primitive or evolved,” said Kramers. Objects in the asteroid belt and meteors don’t match it either—and nor does interstellar dust in our arm of the Milky Way galaxy.
Nor is is from a red supergiant star, which are common in the universe—it has too much iron and not enough silicon. Ditto for a supernova type II.
However, Hypatia does fit the profile for something from a supernova type Ia, which happen once or twice per galaxy per century and are responsible for creating most of the iron in the universe.
Wishing you clear skies and wide eyes.