Searching for the Origins of Presolar Grains

Some meteorites contain microscopic grains of stardust created by nucleosynthesis before our solar system existed. Many grains contain sulfur isotopes that are clues to the grains’ origins in novae and supernovae. Sulfur production from nucleosynthesis depends on the prior production of argon-34. Scientists created and studied argon-34 and established criteria for determining whether particular grains originated in novae or supernovae.