Aluminum-, Calcium- and Titanium-rich Oxide Stardust in Ordinary Chondrite Meteorites

By L. Nittler, C. Alexander, Roberto Gallino, P. Hoppe, A. Nguyen, F. Stadermann, E. Zinner. 2008

173 citations recorded by the source corpus.

We report O-, Al-Mg-, K-, Ca-, and Ti-isotopic data for a total of 96 presolar oxide grains found in residues of several unequilibrated ordinary chondrite meteorites. Identified grain types include Al2O3, MgAl2O4, hibonite (CaAl12O19), and Ti oxide. This work greatly increases the presolar hibonite database, and is the first report of presolar Ti oxide. O-isotopic compositions of the grains span previously observed ranges and indicate an origin in red giant and asymptotic giant branch (AGB) stars of low mass (<2.5 M☉) for most grains. Cool bottom processing in the parent AGB stars is required to explain isotopic compositions of many grains. Potassium-41 enrichments in hibonite grains are attributable to in situ decay of now-extinct 41Ca. Inferred initial 41Ca/40Ca ratios are in good agreement with model predictions for low-mass AGB star envelopes, provided that ionization suppresses 41Ca decay. Stable Mg and Ca isotopic ratios of most of the hibonite grains reflect primarily the initial compositions of the parent stars and are generally consistent with expectations for Galactic chemical evolution, but require some local interstellar chemical inhomogeneity. Very high 17O/16O or 25Mg/24Mg ratios suggest an origin for some grains in binary star systems where mass transfer from an evolved companion has altered the parent star compositions. A supernova origin for the hitherto enigmatic 18O-rich Group 4 grains is strongly supported by multielement isotopic data for two grains. The Group 4 data are consistent with an origin in a single supernova in which variable amounts of material from the deep 16O-rich interior mixed with a unique end-member mixture of the outer layers. The Ti oxide grains primarily formed in low-mass AGB stars. They are smaller and rarer than presolar Al2O3, reflecting the lower abundance of Ti than Al in AGB envelopes.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/d160edc4141fce94f9d78451f8ccb974259bf13a

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In Astronomy and Astrophysics

1. C. Kobayashi
2. A. Karakas
3. H. Umeda
4. F. Ciesla
5. A. Nguyen
6. P. Hoppe
7. L. Nittler
8. M. Lugaro

Citations in the corpus

• Astrophysics with Extraterrestrial Materials (2016, background): “…to have originated in SN have 18Oand 17O-rich signatures, best explained as mixtures of small amounts of material from inner zones (mainly the 18O-rich He-rich layer, but also 24Mg and 44Ti from deeper layers) with larger contributions from the massive star’s H-rich envelope (Nittler et al. 2008).”
• Ultra-primitive interplanetary dust particles from the comet 26P/Grigg–Skjellerup dust stream collection (2009, background): “Rather, Nittler et al. (2008) recently argued that these unusual grains are related to the 18O-rich Group 4 grains and likely formed in one or more supernovae.”
• The evolution of isotope ratios in the Milky Way Galaxy (2011, methodology): “Attempts have been made to use meteoritic data to trace the chemical enrichment history of the Milky Way, although this has been done only for a limited number of elements including O, Mg (Nittler et al. 2008; Nittler 2009), and Si (Lugaro 1999; Zinner et al. 2006).”
• NanoSIMS: Technical Aspects and Applications in Cosmochemistry and Biological Geochemistry (2013, unknown): “In a combined IMS6f/NS50/NS50L study, Nittler et al. (2008) measured O, Mg, Al and K–Ca isotopic compositions of several oxide grains in three separate analysis set-ups.”