HMC Physics Colloquium

Tuesdays at 16:30 in Shanahan Center for Teaching and Learning, Room B460

Gerardo Dominguez

University of California at San Diego

Isotope Studies in Natural Systems and Their Applications

Feb. 9, 2010

The abundance of isotopes of an element can vary as a function of time and space. A thorough understanding of the physical and chemical factors that underlie these variations can be used to reconstruct the natural history of the Earth, the planets, and even the interstellar medium. In this talk, I will discuss factors that lead to small but measurable differences in the abundance of $$^{16}\mathrm{O}$$, $$^{17}\mathrm{O}$$, $$^{18}\mathrm{O}$$ in natural systems, with a specific emphasis on so-called "mass-dependent" and "mass-independent" enrichment processes. Several applications of conventional and mass-independent isotope fractionations will be presented. I will end by describing the anomalous distribution of oxygen isotopes in the solar system (including the sun) and a chemical mechanism on interstellar dust grains in cold-molecular clouds that may explain why the sun is anomalously enriched in $$^{16}\mathrm{O}$$ compared to the rest of the solar system.