Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Brief Follow-up on Recent Studies of Theia's Accretion   Kaib & Cowan (2015) recently used terrestrial planet formation simulations to
conclude that the moon-forming impactor (Theia) had only a ~5% or less chance
of having the same oxygen isotope composition as Earth, while
Mastrobuono-Battisti et al. (2015) used seemingly similar simulations and
methods to arrive at a higher value of ~20% or more. Here we derive the results
of both papers from a single set of simulations. Compared to Kaib & Cowan
(2015), the analysis of Mastrobuono-Battisti et al. (2015) systematically
yields more massive Theia analogs and imposes flatter isotopic gradients across
the original protoplanetary disk. Both of these effects diminish isotopic
differences between Earth and Theia analogs. While it is notoriously difficult
to produce systems resembling our actual terrestrial planets, the analysis of
Kaib & Cowan (2015) more often selects and analyzes Earth and Mars analogs at
orbital locations near the real planets. Given this, we conclude that the
greater isotopic differences between Earth and Theia found in Kaib & Cowan
(2015) better reflect the predictions of terrestrial planet formation models.
Finally, although simulation uncertainties and a terrestrial contribution to
Moon formation enhance the fraction of Theia analogs consistent with the
canonical giant impact hypothesis, this fraction still remains in the 5-8%
range.

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The categories of this paper are: physics
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The categories of this paper are: gr-qc
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The categories of this paper are: quant-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: dg-ga
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The categories of this paper are: alg-geom
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-th
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The categories of this paper are: chem-ph
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The categories of this paper are: adap-org
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The categories of this paper are: nucl-ex
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The categories of this paper are: math
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The categories of this paper are: q-alg
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-ph
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The categories of this paper are: plasm-ph