Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dynamics of Massive Shells Ejected in a Supernova Explosion   An expanding shell is accelerated outward by radiation from the remnant star
and slowed by ram pressure and accretion as it plows into the interstellar
medium. We set up the general relativistic equations of motion for such a
shell. In the non-relativistic limit, the reduce to the standard Ostriker-Gunn
equations. Furthermore, it is shown that the motion equation can be integrated
in general, reducing in this way the study of the dynamics of a shell to a set
of four coupled first order differential equations, solvable up to quadrature

22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys