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Ashes of a dying star hold clues about solar system's birth

A team of researchers has discovered a grain of dust forged in the death throes of a long-gone star. The discovery challenges some of the current theories about how dying stars seed the universe with raw materials for the formation of planets and, ultimately, the precursor molecules of life. Tucked inside a chondritic meteorite -- a stony meteorite that has not been modified due to melting or differentiation of the parent body -- collected in Antarctica, the tiny speck represents actual stardust, most likely hurled into space by an exploding star before our own sun existed. Although such grains are believed to provide important raw materials contributing to the mix from which the sun and our planets formed, they rarely survive the turmoil that goes with the birth of a solar system. Dubbed LAP-149, the dust grain represents the only known assemblage of graphite and silicate grains that can be traced to a specific type of stellar explosion called a nova. Remarkably, it survived the journey through interstellar space and traveled to the region that would become our solar system some 4.5 billion years ago, perhaps earlier, where it became embedded in a primitive meteorite.

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