Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Characteristics of hybrid compact stars with a sharp hadron-quark
  interface   We describe two aspects of the physics of hybrid stars that have a sharp
interface between a core of quark matter and a mantle of nuclear matter.
  Firstly, we analyze the mass-radius relation. We describe a generic "Constant
Speed of Sound" (CSS) parameterization of the quark matter equation of state
(EoS), in which the speed of sound is independent of density. In terms of the
three parameters of the CSS EoS we obtain the phase diagram of possible forms
of the hybrid star mass-radius relation, and we show how observational
constraints on the maximum mass and typical radius of neutron stars can be
expressed as constraints on the CSS parameters.
  Secondly, we propose a mechanism for the damping of density oscillations,
including r-modes, in hybrid stars with a sharp interface. The dissipation
arises from the periodic conversion between quark matter and nuclear matter
induced by the pressure oscillations in the star. We find the damping grows
nonlinearly with the amplitude of the oscillation and is powerful enough to
saturate an r-mode at very low saturation amplitude, of order $10^{-10}$, which
is compatible with currently-available observations of neutron star spin
frequencies and temperatures.

27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
7
The categories of this paper are: hep-th