Meteorites Peppered With Ancient Supernova Star Dust

Microscopic dust grains extracted from meteorites that landed on Earth had ancient and explosive origins, scientists have discovered.

The dust grains - also known as presolar grains, since they're older than Earth's sun - were likely spewed out by stars that blew up hundreds of millions of years before Earth's solar system formed. And in a new analysis of data collected from these tiny particles, researchers have come closer to pinpointing the type of stellar blast that produced the dust, 5 billion years ago.

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To trace the origins of the stardust's subatomic "fingerprints," scientists built computer models simulating the explosive conditions that could have produced them, to test whether the dust grains' point of origin might have been an exploding white dwarf star in a double-star system. [Images: Dust Grains from Interstellar Space]

Ancient Grains This study adds to decades of analysis devoted to puzzling out the age and origins of these presolar grains, according to study co-author Christopher Wrede.

Wrede, an assistant professor of physics at Michigan State University, told Live Science in an email that researchers look at the grains' isotopes - variations of an element that have different numbers of neutrons. About a dozen grains held a great deal of the isotope silicon-30, which has been linked to a certain type of stellar explosion called a classical nova.

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Classical novas - stellar eruptions that happen in a binary, or paired, star system - are different from supernovas, Wrede said, in that they are a type of explosion that can happen over and over again. The smaller star in a pair, a white dwarf, steals fuel from its larger neighbor, heating up its own surface and eventually blasting dust and gas into space.

"After a classical nova, the white dwarf can continue to siphon fuel from the companion and ignite again," Wrede said. "In a supernova, the entire star explodes, so it can only happen once."

Going Nuclear When Earth's solar system was forming, collisions heated and mixed the building blocks of dust and gas, cooking them uniformly so that they shared many of the same isotopes. Grains with unusual isotopes - like silicon-30, which is rare on Earth - stand out, Wrede explained. "This tells us that they must have been produced prior to the formation of the solar system," dating back around 5 billion years, Wrede said.

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According to Wrede, the high quantities of silicon-30 compared to other silicon isotopes in the grains suggested that they originated in a classical nova, but he and his colleagues were unsure just how much silicon-30 they could expect to see, relative to the other isotopes, if a classical nova were responsible. Their experiments revealed a new pathway for a nuclear reaction that would affect the amount of silicon-30 produced, and will help determine if the amount of silicon-30 in the dust grains is a match.

"The pathway seems to be a strong one, but we'll need to do more experiments to find out how strong," Wrede told Live Science.

The findings were published online March 8 in the journal Physical Review Letters.

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An artist's rendering of an exploding star. Billions of years ago, dust from a stellar explosion like this may have made its way to Earth.

Dozens of videos of the Russian meteor were uploaded to Youtube soon after impact on the morning of Feb. 15, 2013, many of which originated from vehicle dashboard cameras (or "dash cams"). During the morning commute many drivers saw the bright orb grow and explode in the atmosphere. The resulting shock wave caused windows to blow out over a huge area injuring over 1,000 people -- mainly cuts and minor concussions.

The fireball light was as bright as a second sun for a brief moment before it broke up over the Urals region of Russia.

As seen in this CCTV footage, the meteor created its own shadows as it exploded during the morning commute.

The meteor contrail hung over the Urals city of Chelyabinsk, about 900 miles east of Moscow, for some time after impact.

A white contrail left by the meteor break-up over Chelyabinsk.

A building damaged by the meteor shock wave in the town of Kopeisk, Chelyabinsk Region. The windows were blown out by the powerful shock wave generated by the hypersonic meteor.

Damage to a pancake bar caused by the shock wave of a meteor in the town of Kopeisk, Chelyabinsk Region.

Damaged caused to the office of a local newspaper in the Urals city of Chelyabinsk by the shock wave of the meteor.

A shopper walks past a broken shop window caused by the meteor explosion over the Urals city of Chelyabinsk.

The meteor traveled faster than sound in the upper atmosphere, creating a powerful sonic boom that slammed into the populated Urals region -- the foce of the blast blew out windows and caused structural damage to some buildings.

Damage caused by the shock wave of a meteor that passed above the Urals city of Chelyabinsk on Feb. 15, 2013.

Bricks from a factory wall knocked down by the force of the meteor shock wave litter a street in the Urals city of Chelyabinsk.

A collection of small meteorite fragments found in the snow after the Feb. 15, 2013 airbust event.

A man holding meteorite fragments found near the Chebarkul Lake.

Detail of one of the suspected meteorite fragments recovered from Russia's Chelyabinsk region.

Replacing broken window panes destroyed by the shockwave from the meteor airburst, at Uralskaya Molniya ice rink.

Replacing broken window panes destroyed by the shockwave from the meteor airburst, at Uralskaya Molniya ice rink.

Replacing windows in the freezing Chelyabinsk region are a priority for the Russian authorities.

A woman replaces a window damaged by the shockwave of the meteorite fall in Chelyabinsk, Russia, Feb. 16, 2013.

Residents wait for a bus in a street in Chelyabinsk, Russia, Feb. 16, 2013, as life in Russia's Chelyabinsk Region returns to normal after Friday's meteor explosion.