Dr. Andrew Davis
Rocks and Minerals from Stars
One of the most remarkable discoveries of the twentieth century is that some meteorites contain dust grains made around other stars that lived and died more than 4.5 billion years ago, before our Solar System formed. Stars only twice the mass of our Sun eventually turned into red giant stars and lost much of their mass as gas and dust. More massive stars ended with spectacular explosions called supernovae, and throw off much of their mass. Both kinds of stars return copious amounts of dust to the interstellar medium (the stuff between the stars), a portion of which formed new stars like our own, and we have recognized dust grains from both red giants and supernovae in meteorites. Each dust grain retains a chemical and isotopic record of the star around which it formed and by analyzing individual dust grains in the laboratory, we can study the interiors of stars in ways not possible by astronomy with telescopes. The study of stardust in the laboratory has led to new understanding of how the chemical elements are made in stars. Stardust was also not uniformly mixed into the solar nebula, the disk of gas and dust from which the Sun and planets formed. This caused small differences in isotopic composition among Solar System materials that have proven to be powerful tracers of the relationships between planets and different kinds of meteorites.