A collaboration between two Arizona State University scientists -- cosmochemist Maitrayee Bose and astrophysicist Sumner Starrfield, both of ASU's School of Earth and Space Exploration -- has uncovered the connection and pinpointed the kind of stellar outburst that produced the stardust grains.
Their study has just been published in The Astrophysical Journal.
Microscopic - Grains - Silicon - Carbide - Times
The microscopic grains of silicon carbide -- a thousand times smaller than the average width of a human hair -- were part of the construction materials that built the Sun and planetary system. Born in nova outbursts, which are repeated cataclysmic eruptions by certain types of white dwarf stars, the silicon carbide grains are found today embedded in primitive meteorites.
"Silicon carbide is one of the most resistant bits found in meteorites," Bose said. "Unlike other elements, these stardust grains have survived unchanged from before the solar system was born."
Star - Nova - Star - Magnitudes - Novae
A star becomes a nova -- a "new star" -- when it suddenly brightens by many magnitudes. Novae occur in pairs of stars where one star is a hot, compact remnant called a white dwarf. The other is a cool giant star so large its extended outer atmosphere feeds gas onto the white dwarf. When enough gas collects on the white dwarf, a thermonuclear eruption ensues, and the star becomes a nova.
Although powerful, the eruption doesn't destroy the white dwarf or its companion, so novae can erupt over and over, repeatedly throwing into space gas and dust grains made in the explosion. From there the dust grains merge with clouds of interstellar gas to become the ingredients of new star systems.
Sun - System - Years - Cloud - Dust
The Sun and solar system were born about 4.6 billion years ago from just such an interstellar cloud, seeded with dust grains from earlier stellar eruptions by many different kinds of stars. Almost all the original grains were consumed in making the...
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