Date of Award
12-2013
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Legacy Department
Physics
Committee Chair/Advisor
Meyer, Bradley S
Committee Member
Brittain, Sean D
Committee Member
Hartmann, Dieter H
Committee Member
Sosolik, Chad E
Abstract
Calcium-aluminum-rich inclusions (CAIs) are millimeter-sized refractory objects found in primitive meteorites. CAIs are considered as some of the first solids to form in the solar system, because they are refractory. FUN CAIs, those with Fractionated and Unknown Nuclear effects, are a small subset of CAIs. These FUN CAIs show correlated excesses and deficits in the neutron-rich iron-group isotopes such as 48 Ca and 50 Ti which regular CAIs do not. Interestingly, these isotopes are most likely produced infrequently but in huge quantities in a rare class of thermonuclear (Type Ia) supernovae. I propose that the isotopic effects in the neutron-rich iron-group nuclei in FUN CAIs arise from the rarity (~2%) of the Type Ia supernovae that produce them. To quantitatively test this hypothesis we built a simple Ia model to get the yields and trajectories, and then estimated the chemical forms and sizes of dust grains into which those isotopes condense. Our results show that these rare dense Type Ia supernovae can produce a large quantity of neutron-rich iron-group isotopes; with unburned carbon and oxygen added the chemical perovskite (CaTiO 3 ) would form and may count for more than 5% of total atoms in the outflow; the size of dust grains can grow up to the order of 0.1 micron. All these findings suggest the rare dense Type Ia supernovae may be the source of these isotopes and the outflows may form Ca-Ti carriers which will bring the heterogeneity of these isotopes to the early solar system. The future Galactic Chemical Evolution simulation with these inputs would help constrain the Solar System formation in the nucleosynthetic and dust formation aspects.
Recommended Citation
YU, TIANHONG, "CHEMICAL EVOLUTION OF THE NEUTRON-RICH IRON-GROUP ISOTOPES AND IMPLICATIONS FOR THE FORMATION OF FUN CAIS" (2013). All Dissertations. 1244.
https://open.clemson.edu/all_dissertations/1244