Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Orbital evolution under the action of fast interstellar gas flow with
  non-constant drag coefficient   The acceleration of a spherical dust particle caused by an interstellar gas
flow depends on the drag coefficient which is, for the given particle and flow
of interstellar gas, a specific function of the relative speed of the dust
particle with respect to the interstellar gas. We investigate the motion of a
dust particle in the case when the acceleration caused by the interstellar gas
flow represent a small perturbation to the gravity of a central star. We
present the secular time derivatives of the Keplerian orbital elements of the
dust particle under the action of the acceleration from the interstellar gas
flow for arbitrary orbit orientation. The semimajor axis of the dust particle
is a decreasing function of time for an interstellar gas flow acceleration with
constant drag coefficient and also for such an acceleration with the linearly
variable drag coefficient. The decrease of the semimajor axis is slower for the
interstellar gas flow acceleration with the variable drag coefficient. The
minimal and maximal values of the decrease of the semimajor axis are
determined. In the planar case, when the interstellar gas flow velocity lies in
the orbital plane of the particle, the orbit always approaches the position
with the maximal value of the transversal component of the interstellar gas
flow velocity vector measured at perihelion.
  The properties of the orbital evolution derived from the secular time
derivatives are consistent with numerical integrations of the equation of
motion. If the interstellar gas flow speed is much larger than the speed of the
dust particle, then the linear approximation of dependence of the drag
coefficient on the relative speed of the dust particle with respect to the
interstellar gas is usable for practically arbitrary (no close to zero) values
of the molecular speed ratios (Mach numbers).

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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-th
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The categories of this paper are: cs
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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: math-ph
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The categories of this paper are: adap-org
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-ex
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The categories of this paper are: solv-int
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The categories of this paper are: hep-th
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The categories of this paper are: quant-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: supr-con
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The categories of this paper are: mtrl-th