2011 Annual Science Report
Arizona State University Reporting | SEP 2010 – AUG 2011
Astrophysical Controls on the Elements of Life, Task 5: Model the Variability of Elemental Ratios Within Clusters
In Tasks 3 and 4 we study how supernovae may enrich indvidual solar systems at the peripheries of high-mass star-forming regions. In this task we study in a statistical sense how stars of a variety of masses at the ends of their lives enrich star-forming molecular clouds and stellar clusters. Through detailed numerical hydrodynamic simulations we are studying the mixing of heavy elements into the surrounding medium and comparing our predictions to variable abundance ratios in present-day clusters. We also apply this research to star formation in the early universe, studying the transition between pristine (very low metallicity) and enriched star formation.
The past year has led to two published articles related to this topic, and a third one submitted. Two of these describe the results of the first ever simulations of the mixing of material by supersonic turbulence of the type that occurs in star forming molecular clouds (Pan & Scannapieco 2010, 2011). In the third of these (Pan et al. 2011), we bought in a new collaborator, John Scalo, from UT Austin and extended our approach to study the self-enrichment of clusters in the early universe. Here we derived new results constraining the transition from primordial star formation, in which stars are made purely of hydrogen in helium, to “Population II” star formation, in which stars are enriched with heavy elements and surrounded by protostellar disks that may form planets. This work was presented in several presentations, including an invited talk by E.Scannapieco at the Kavli Institute for Theoretical Physics program on the Nature of Turbulence, and invited talks by L. Pan at the Institute of Mechanics, Chinese Academy of Sciences.