Microstructural Study of an 18-O-Poor Presolar Silicate Grain from The Meteorite Hills 00426 Cr2 ChondriteThe majority of presolar silicate and oxide grains derive from low-mass red giant and asymptotic giant branch (AGB) stars of approximately solar metallicity (Z). A small subclass of presolar O-rich grains (less than 7%) is thought to originate from stars having lower-than-solar Z. These "Group 3" [1] grains have depletions in 18O and 17O that typically fall along or above the Galactic chemical evolution (GCE) line. Other Group 3 grains show greater 17O than 18O depletions and most likely have supernova (SN) origins. Owing to their rarity, only two Group 3 silicates have been mineralogically examined in detail [2, 3]. Here we present a mineralogical study of a Group 3 presolar silicate to explore its formation conditions and interstellar history.
Document ID
20170006951
Acquisition Source
Johnson Space Center
Document Type
Abstract
Authors
Nguyen, A. N. (Jacobs Technology, Inc. Houston, TX, United States)
Keller, L. P. (NASA Johnson Space Center Houston, TX, United States)
Messenger, S. (NASA Johnson Space Center Houston, TX, United States)