Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evolutionary trajectories of ultra-compact "black widow" pulsars with
  very low mass companions   The existence of millisecond pulsars with planet-mass companions (Bailes et
al., 2011) in close orbits is challenging from the stellar evolution point of
view. We calculate in detail the evolution of binary systems self-consistently,
including mass transfer, evaporation and irradiation of the donor by X-rays
feedback, demonstrating the existence of a new evolutionary path leading to
short periods and compact donors as required by the observations of PSR
J1719-1438. We also point out the alternative of an exotic nature of the
companion planet-mass star.

31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th