Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Long-Term evolution of Discs around Magnetic Stars   We investigate the evolution of a thin viscous disc surrounding magnetic
star, including the spindown of the star by the magnetic torques it exerts on
the disc. The transition from an accreting to a non-accreting state, and the
change of the magnetic torque across the corotation radius are included in a
generic way, the widths of the transition taken in the range suggested by
numerical simulations. In addition to the standard accreting state, two more
are found. An accreting state can develop into a 'dead' disc state, with inner
edge well outside corotation. More often, a 'trapped' state develops, in which
the inner disc edge stays close to corotation even at very low accretion rates.
The long-term evolution of these two states is different. In the dead state the
star spins down incompletely, retaining much of its initial spin. In the
trapped state the star asymptotically can spin down to arbitarily low rates,
its angular momentum transferred to the disc. We identify these outcomes with
respectively the rapidly rotating and the very slowly rotating classes of Ap
stars and magnetic white dwarfs.

12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat