Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A chemical study of M67 candidate blue stragglers and evolved blue
  stragglers observed with APOGEE DR14   Within the variety of objects populating stellar clusters, blue straggler
stars (BSSs) are among the most puzzling ones. BSSs are commonly found in
globular clusters, but they are also known to populate open clusters of the
Milky Way. Two main theoretical scenarios (collisions and mass transfer) have
been suggested to explain their formation, although finding observational
evidence in support of either scenario represents a challenging task. Among the
APOGEE observations of the old open cluster M67, we found 8 BSS candidates
known from the literature and two known evolved BSSs. We carried out a chemical
analysis of 3 BSS candidates and of the 2 evolved BSSs out of the sample and
found that the BSS candidates have surface abundances similar to those of stars
on the main-sequence turn-off of M67. Especially the absence of any anomaly in
their carbon abundances seems to support a collisional formation scenario for
these stars. Furthermore, we note that the abundances of the evolved BSSs S1040
and S1237 are consistent with the abundances of the red clump stars of M67. In
particular, they show a depletion in carbon by $\sim0.25$ dex, which could be
either interpreted as the signature of mass transfer or as the product of
stellar evolutionary processes. Finally, we summarise the properties of the
individual BSS stars observed by APOGEE, as derived from their APOGEE spectra
and/or from information available in the literature.

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The categories of this paper are: quant-ph
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The categories of this paper are: funct-an
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The categories of this paper are: alg-geom
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The categories of this paper are: comp-gas
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The categories of this paper are: gr-qc
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The categories of this paper are: acc-phys
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The categories of this paper are: chem-ph
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The categories of this paper are: math
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The categories of this paper are: adap-org
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The categories of this paper are: hep-th
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The categories of this paper are: stat
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The categories of this paper are: hep-lat
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The categories of this paper are: supr-con
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The categories of this paper are: solv-int
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The categories of this paper are: q-bio
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The categories of this paper are: ao-sci