Presolar grains circumstellar condensates

There are two types of presolar grains. Circumstellar condensates condensed from hot gas ejected from dying stars in the immediate vicinity of their parent stars. They are also sometimes called stardust. Circumstellar condensates give snapshots of the life histories of the stars from which they formed. Although the stars themselves no longer exist, the... 

As noted previously, most of the presolar grains so far identified are circumstellar condensates (stardust), but some grains formed in interstellar space. The interstellar grains are not likely to contain large isotopic anomalies. So how can we recognize these interstellar grains in meteorites ... 

Goldschmidt, Suess, and Urey showed that chondrites provide the best estimates for the mean abundances of condensable elements in the solar system. These estimates were essential for developing theories for the formation of elements in evolved stars (see Chapters 1.01 and 1.03). Presolar grains (see Chapter 1.02) provide additional clues to nucleosynthesis and the subsequent growth of circumstellar grains. Chondrules, metal grains, refractory inclusions, and matrix materials formed under very diverse conditions in the solar system and appear to offer... 

AGB stars return -0.3 solar masses per year to the interstellar medium (ISM) in our galaxy (65), of which C stars contribute about 10-50% (14, 30). Thus, dust condensation in the circumstellar envelopes of C stars is a plausible source of the presolar C-bearing grains found in meteorites. Although... 

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