Presolar grains properties

In contrast, the study of stellar grains permits information to be obtained about individual stars, complementing astronomical observations of elemental and isotopic abundances in stars (e.g., Lambert, 1991), by extending measurements to elements that cannot be measured astronomically. In addition to nucleosynthesis and stellar evolution, presolar grains provide information about galactic chemical evolution, physical properties in stellar atmospheres, mixing of SN ejecta and conditions in the parent bodies of the meteorites in which the grains are found. 

Trace quantities of refractory presolar grains (e.g., SiC and AI2O3) survive in the matrices of the most primitive carbon-rich chondritic meteorites (Anders and Zinner, 1993 Bernatowicz and Zinner, 1996 Bernatowicz and Walker, 1997 Hoppe and Zinner, 2000 see Chapter 1.02). Chondritic meteorites are believed to be from the asteroid belt, a narrow region between 2.5 and 3.5 astronomical units (AU) that marks the transition from the terrestrial planets to the giant gas-rich planets. The spectral properties of the asteroids suggest a gradation in properties with... 

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