Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The strange close binary V405 And: the influence of different dynamos on
  the components   V405 And is a fast-rotating (P=0.465d) grazing eclipsing binary with two
active components. Using multicolor photometric monitoring and radial velocity
measurements, we find that the primary and the secondary components have masses
of 0.49 and 0.21 solar masses, meaning that the primary probably possesses a
radiative core and a convective envelope, while the secondary is fully
convective. The radius of the low-mass component fits well the theoretical
mass-radius relation. However, the radius of the primary is significantly
larger than the predicted value, in fact, the discrepancy is far the highest
from the four similar objects known.

25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs