LAUSR

Introduction: Primitive chondrititc meteorites contain mmto cm-sized assemblages of Caand Albearing oxides and silicates. So-called calcium-aluminum-rich inclusions (CAIs) have radiometric age dates of 4.5673 Ga, exceeding those of all other solar-system materials [1]. Moreover, equilibrium thermodynamic calculations show that the materials within CAIs formed at very high (>1300 K) temperatures [2]. Analysis of these objects can therefore provide insight into chemical and physical processes that occurred in the early solar system. Perovskite, nominally CaTiO3, occurs within primitive CAIs. It is the major Ti-bearing phase in these refractory inclusions, and is thermodynamically predicted to condense at 1593K [2]. We examined perovskite structure and composition down to the atomic level to better understand the thermodynamic conditions in which these refractory materials formed.