Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Finding magnetic north: an extraordinary magnetic field detection in
  Polaris and first results of a magnetic survey of classical Cepheids
5
The categories of this paper are: gr-qc
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
20
The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph