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A tiny star dust, hidden in a meteorite of Antarctica, is probably older than our sun – and was catapulted into our celestial neighborhood by an ancient star explosion prior to the formation of our solar system.
This old seed is only 1 / 25,000 of an inch, shaped like a "crescent" and could tell us more about the origins of our solar system, researchers said April 29 in the journal Nature Astronomy.
Using several types of microscopes, these researchers scrutinized star dust and discovered that it was composed of a combination of graphite (a form of carbon) and silicate (a salt composed of silicon and oxygen). When scientists compared this composition to models, they determined that it probably came from a specific type of stellar explosion called nova. [Fallen Stars: A Gallery of Famous Meteorites]
Nova's explosions occur during the exchange of energy between an ordinary star and a white dwarf, a star that has burned most of its nuclear fuel. The white dwarf feeds on the other star, accumulating enough new material to rekindle into powerful shards that burst into space. This is how the star dust sample, called LAP-149, was formed and then crossed the interstellar space to the proximity of our solar system.
"These grains of star dust look like fossilized relics of ancient stars," Tom Zega, an associate professor at the Lunar and Planetary Laboratory at the University of Arizona, told Live Science. . In addition, researchers know that this star dust must have traveled far, because it contains high levels of a very specific form, or isotope, of carbon (carbon 13). Such levels are not visible in any sampled object in our solar system, Zega said.
Star explosions throw the ingredients into interstellar space, where they eventually serve as seeds for the planets. Thus, according to a statement, rare discoveries like this ancient grain could enlighten us on the formation of our solar system.
The results provide further evidence that carbon-rich and oxygen-rich grains from nova explosions contributed to the construction of the solar system. Although the grain is too small for researchers to date, they have guessed, based on its composition and the meteorite from which it comes, that it was at least 4.5 billion years old – at about the time where our solar system is formed.
"It's the ashes of different kinds of stars that have disappeared or are about to disappear from the universe," Zega said. "Moreover, because we find them preserved inside the meteorites and we can age dated meteorites with the help of radioisotopes, we know that they must be older than the meteorite itself. " Meteorites such as LAP-149 are "very primitive" and are part of "leftovers after sun and planet formation," he added.
Zega and his team hope to find and analyze larger specimens of star dust in the future, which they hope to be able to date.
In any case, the very existence of this primordial grain of history is astonishing, the researchers said. "It's remarkable when you think of all [events] along the way that should have killed this grain, "said Zega in his statement.
Originally published on Science live.
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