“Standard candle” (or Type Ia) supernova explosions are among the most energetic events in the Universe, occurring when a dense white dwarf subsumes another star. Now scientists believe they have found the first evidence on Earth of such a supernova.
The claim comes after careful study of the alien stone Hypatia which was found in Egypt in 1996. Telltale signs, including the rock’s chemical composition and patterning, suggest the shards contain chunks of dust and gas cloud surrounding a supernova Ia.
Over billions of years, this mixture of dust and gas would have turned into a solid, the researchers say, eventually forming the parent body from which Hypatia emerged near the birth of our solar system.
“In a sense, you could say we caught a supernova Ia explosion red-handed, because the gas atoms from the explosion were captured in the surrounding dust cloud, which eventually formed the parent body of Hypatia,” says geochemist Jan Kramers of the University. from Johannesburg in South Africa.
Using detailed, non-destructive chemical analysis techniques, the team examined 17 different targets on a small sample of Hypatia. From there, it was a matter of piecing together clues as to where the stone had been and how it formed.
These clues included an unusually low level of silicon, chromium and manganese, suggesting that the rock did not form in the inner solar system. The researchers also noticed elevated levels of iron, sulfur, phosphorus, copper and vanadium, again making the object distinct from anything in our particular neighborhood in space.
Looking at Hypatia’s element concentration patterns, there were stark differences from what we would expect to have formed in rocks in the solar system’s interior and in our arm of the Milky Way. Further analysis rules out the idea that the rock had formed from a red giant star.
The researchers were also able to show that Hypatia was not what one would expect if it came from a type II supernova – it contains too much iron compared to silicon and calcium – and this leaves the possibility intriguing that it is a remnant of a Type Ia supernova, and the first discovery on this planet.
“If this hypothesis is correct, the Hypatia Stone would be the first hard evidence on Earth of a Type Ia supernova explosion,” says Kramers.
“Perhaps equally important, it shows that an anomalous individual package of dust from outer space could actually be incorporated into the solar nebula from which our solar system was formed, without being completely mixed together. “
From what we know of Type Ia supernovae, they should produce very unusual patterns of element concentration in rocks such as Hypatia. Through extensive research of star data and modeling, the team was unable to find a better match for the rock.
Of the 15 elements analyzed in the stone, several matched what one would expect if the object came from a dense explosion of white dwarf stars.
However, this is not yet a closed case. Six other elements do not fit the Type 1a supernova models: aluminum, phosphorus, chlorine, potassium, copper, and zinc. However, the researchers think something further in the supernova’s past could explain this.
“Since a white dwarf star is formed from a dying red giant, Hypatia could have inherited these element proportions for the six elements of a red giant star,” Kramers explains. “This phenomenon has been observed in white dwarf stars in other research.”
We’ll need more research to establish the science, but at this point it certainly seems like this mysterious rock has come a very long way.
The research has been published in Icarus.