2012- 21st Annual NC State Undergraduate Research Symposium

Session Time : 4/10/12 12:15 PM - 4/10/12 1:30 PM

Content Area : Physics

Poster Appointment: NONE

Student Presenters :
Scott Robert Akerman Physics

Mentors and/or Co-Authors :
Carla Frohlich Physics

Abstract Title : Effect of type II supernovae on the weak s-process in low-metallicity rotating stars.

Abstract :
Massive stars and their supernovae dominate the early evolution of galaxies and seed their chemical enrichment. These supernovae synthesize and eject intermediate-mass and iron-group elements, and may be a site for the synthesis of the heaviest elements. However, the origin of some of the lighter heavy elements (between iron and the rapid neutron-capture process elements at mass number A=130) is not well understood at low metallicity. Recent observations of low-metallicity stars have shown an enhanced primary nitrogen content that is higher than traditional non-rotating stellar models predict but is consistent with improved models which include the effects of stellar rotation. An elevated primary nitrogen abundance implies an increased amount of ²²Ne which may allow for the weak component of the slow neutron-capture process (weak s-process) to produce greater yields of heavy elements. Using data from a recent evolution of a low-metallicity rotating 15 Msun star we simulate a Type II supernova explosion and analyze the effect of the shock wave on weak s-process yields. The shock wave is artificially initiated by a burst of pressure at 1.4 Msun with an energy such that 1 foe is observed in the ejecta. Temperatures which allow for the weak s-process are achieved but the primary yields are light elements with only minor increases in the yields of heavy elements.