Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On some gravitomagnetic spin-spin effects for astronomical bodies   In this paper we look at the gravitational spin--spin interaction between
macroscopic astronomical bodies. In particular, we calculate their
post--Newtonian orbital effects of order $\mathcal{O}(c^{-2})$ on the
trajectory of a spinning particle with proper angular momentum ${\bf s}$ moving
in the external gravitomagnetic field generated by a central spinning mass with
proper angular momentum ${\bf J}$. It turns out that, at order $\mathcal{O}(e)$
in the orbiter's eccentricity, the eccentricity the pericenter and the mean
anomaly rates of the moving particle are affected by long--term harmonic
effects. If, on one hand, they are undetectable in the Solar System, on the
other, maybe that in an astrophysical context like that of the binary
millisecond pulsars there will be some hopes of measuring them in the future.

35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex