Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A study of non-Keplerian velocities in observations of spectroscopic
  binary stars   This paper presents an orbital analysis of six southern single-lined
spectroscopic binary systems. The systems selected were shown to have circular
or nearly circular orbits (e < 0.1) from earlier published solutions of only
moderate precision. The purpose was to obtain high-precision orbital solutions
in order to investigate the presence of small non-Keplerian velocity effects in
the data and hence the reality of the small eccentricities found for most of
the stars.
  The Hercules spectrograph and 1-m McLellan telescope at Mt John Observatory,
New Zealand, were used to obtain over 450 CCD spectra between 2004 October and
2007 August. Radial velocities were obtained by cross-correlation. These data
were used to achieve high-precision orbital solutions for all the systems
studied, sometimes with solutions up to about 50 times more precise than those
from the earlier literature. However, the precision of the solutions is limited
in some cases by the rotational velocity or chromospheric activity of the
stars.
  The data for the six binaries analysed here are combined with those for six
stars analysed earlier by Komonjinda, Hearnshaw and Ramm.We have performed
tests using the prescription of Lucy on all 12 binaries, and conclude that,
with one exception, none of the small eccentricities found by fitting Keplerian
orbits to the radial-velocity data can be supported. Instead we conclude that
small non-Keplerian effects, which are clearly detectable for six of our stars,
make impossible the precise determination of spectroscopic binary orbital
eccentricities for many late-type stars to better than about 0.03 in
eccentricity, unless the systematic perturbations are also carefully modelled.
The magnitudes of the non-Keplerian velocity variations are given
quantitatively.

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The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
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The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: dg-ga
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The categories of this paper are: atom-ph
11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
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The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
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The categories of this paper are: adap-org