  It is generally accepted that Einstein's theory will get some as yet unknown
corrections, possibly large in the strong field regime. An ideal place to look
for these modifications is around the vicinities of compact objects such as
black holes. Our case study here are Dilatonic Black Holes, which arise in the
framework of Gauss-Bonnet couplings and one-loop corrected four-dimensional
effective theory of heterotic superstrings at low energies. These are
interesting objects as a prototype for alternative, yet well-behaved gravity
theories: they evade the "no-hair" theorem of General Relativity but were
proved to be stable against radial perturbations. We investigate the viability
of these black holes as astrophysical objects and try to provide some means to
distinguish them from black holes in General Relativity. We start by extending
previous works and establishing the stability of these black holes against
axial perturbations. We then look for solutions of the field equations
describing slowly rotating black holes and study geodesic motion around this
geometry. Depending on the values of mass, dilaton charge and angular momentum
of the solution, one can have measurable differences in the ISCO location and
orbital frequency, relatively to black holes in General Relativity. Such
differences may be useful in future experiments, to discriminate between
alternative theories of gravity.
