  Neutron stars can be considered a useful and interesting laboratory for
Cosmology. With their deep gravitational potential they may accrete dark matter
from the galactic halo and subsequent self-annihilation processes could induce
an indirect observable signal this type of matter. In addition, the large
densities in the interior of these objects may constitute a test-bench to study
hypothesized deviations of fundamental constant values complementary to
existing works using constraints at low density from BBN.
