ACP Seminar (Astronomy - Cosmology - Particle Physics)

Speaker: Johannes Andersen and Birgitta Nordstrom (The Niels Bohr Institute, Copenhagen)
Title: The Origin of the Elements in the Universe
Date (JST): Fri, Oct 28, 2011, 13:30 - 15:00
Place: Seminar Room A
Abstract: After the Big Bang and recombination, the Universe consisted of pure hydrogen and helium, with a tiny amount of lithium. When the first, short-lived, stars arrived on the scene, they seeded the first galaxies with the first heavier elements, presumably starting with C, N and O, and paved the way for the formation of low-mass, long-lived stars that could survive until today. The heavy-element content gradually grew from maybe 0.001% to 0.5% of that of the Sun, and the periodic system was populated all the way up to Th and U, in proportions that we can measure in detail in meteorites and through
physical processes that are largely understood. After that stage, more highly differentiated structures such as globular clusters and galaxies formed, and the trail becomes difficult to follow. However, the chemical composition of the earlier generations of stars can be studied in great detail, while their origin is still relatively simple. The talk will discuss results from a large programme of this kind, covering Li, CNO, and the heaviest elements, in terms of both nucleosynthesis and what can be learned about the structure of the primitive Galaxy/galaxies.