Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Twins Among the Low Mass Spectroscopic Binaries   We report an analysis of twins of spectral types F or later in the 9th
Catalog of Spectroscopic Binaries (SB9). Twins, the components of binaries with
mass ratio within 2% of 1.0, are found among the binaries with primaries of F
and G spectral type. They are most prominent among the binaries with periods
less than 43 days, a cutoff first identified by Lucy. Within the subsample of
binaries with P<43 days, the twins do not differ from the other binaries in
their distributions of periods (median P~7d), masses, or orbital
eccentricities. Combining the mass ratio distribution in the SB9 in the mass
range 0.6 to 0.85 Msun with that measured by Mazeh et al. for binaries in the
Carney-Latham high proper motion survey, we estimate that the frequency of
twins in a large sample of spectroscopic binaries is about 3%. Current
theoretical understanding indicates that accretion of high specific angular
momentum material by a protobinary tends to equalize its masses. We speculate
that the excess of twins is produced in those star forming regions where the
accretion processes were able to proceed to completion for a minority of
protobinaries. This predicts that the components of a young twin may appear to
differ in age and that, in a sample of spectroscopic binaries in a star
formation region, the twins are, on average, older than the binaries with mass
ratios much smaller than 1.

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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: chem-ph
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The categories of this paper are: supr-con
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The categories of this paper are: cmp-lg
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The categories of this paper are: atom-ph
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The categories of this paper are: math
35
The categories of this paper are: mtrl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: acc-phys
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The categories of this paper are: patt-sol
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The categories of this paper are: stat
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The categories of this paper are: cs
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The categories of this paper are: ao-sci
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-ex