Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Aluminum-, Calcium- And Titanium-Rich Oxide Stardust In Ordinary
  Chondrite Meteorites   We report 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 MSun) 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 multi-element 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.

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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ph
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The categories of this paper are: solv-int
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The categories of this paper are: eess
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-th
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The categories of this paper are: funct-an
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The categories of this paper are: plasm-ph
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The categories of this paper are: math
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The categories of this paper are: chem-ph
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The categories of this paper are: stat
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The categories of this paper are: q-alg
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: econ
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The categories of this paper are: chao-dyn