A Complex Presolar Grain in Acfer 094 – Fingerprints of a Circumstellar Condensation Sequence?

Continued Characterization of Presolar Silicate Grains from the Acfer 094 Carbonaceous Chondrite

Introduction: Among circumstellar grains produced around O-rich evolved stars, silicate grains are the most abundant [1]. Until recently, the identification of presolar silicate grains in extraterrestrial materials proved difficult due in part to their destruction by parent body processes, requiring analysis of very primitive samples, and to the experimental challenge presented by their submicr...

Identification of an Extremely O-rich Presolar Silicate Grain in Acfer

Introduction: Presolar silicate grains have been abundantly identified since their first discovery less than a decade ago [1,2,3]. The O isotopic compositions of both silicate and oxide stardust indicate the vast majority (>90%) condensed around O-rich asymptotic giant branch (AGB) stars. Though both presolar phases have average sizes of ~300 nm, grains larger than 1 μm are extremely uncommon f...

Auger Analysis of Presolar Silicates in Acfer 094 & the Discovery of a Presolar Cai

Presolar Fe Oxide from the Acfer 094 Carbonaceous Chondrite

Studies of Minor Phases in Primitive Chondrite Matrix

Introduction: Fine-grained matrix is a major (and thermally the most primitive) component in chondrites. Analyses of chondrite matrix [1] reveal that it does not have a primordial CI-like composition, showing instead a consistent depletion compared to solar in all chondrite groups (except CI). This suggests that volatile depletion was an early event, possibly involving cooling of a hot inner di...