Presolar stardust grains - the oldest datable solid samples
Presolar stardust grains condensed in the outflows of evolved stars and survived residence in the interstellar medium, in the protosolar molecular cloud and in the solar nebula. Presolar grains are found in primitive solar system materials that did not experience much thermal metamorphism. Analyses of presolar grains not only enable us to learn more about nucleosynthesis and mixing in our parent stars but also provide new insights into the lifecycle of dust in the interstellar medium. Dust is a key ingredient to stars and habitable planetary systems, making increased knowledge about its composition and lifecycle desirable. In my talk I will highlight new results from my ongoing work on establishing a presolar chronology from presolar grains' cosmic-ray exposure ages. Our results are discussed in context of theoretical models of interstellar dust lifetimes and have implications on our understanding of the star formation history of our galaxy.