Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Unified Theory for the Effects of Stellar Perturbations and Galactic
  Tides on Oort Cloud Comets   We examine the effects of passing field stars on the angular momentum of a
nearly radial orbit of an Oort cloud comet bound to the Sun. We derive the
probability density function (PDF) of the change in angular momentum from one
stellar encounter, assuming a uniform and isotropic field of perturbers. We
show that the total angular momentum follows a Levy flight, and determine its
distribution function. If there is an asymmetry in the directional distribution
of perturber velocities, the marginal probability distribution of each
component of the angular momentum vector can be different. The constant torque
attributed to Galactic tides arises from a non-cancellation of perturbations
with an impact parameter of order the semimajor axis of the comet. When the
close encounters are rare, the angular momentum is best modeled by the
stochastic growth of stellar encounters. If trajectories passing between the
comet and sun occur frequently, the angular momentum exhibits the coherent
growth attributed to the Galactic tides.

1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc
4
The categories of this paper are: cond-mat
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat