Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Where do long-period comets come from? 26 comets from the
  non-gravitational Oort spike
12
The categories of this paper are: nucl-th
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
29
The categories of this paper are: funct-an
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs