How to take into account the relativistic effects in dynamical studies of comets

Comet-like orbits with low perihelion distances tend to be affected by relativistic effects. In this work we discuss the origin of the relativistic corrections, how they affect the orbital evolution and how to implement these corrections in a numerical integrator. We also propose a model that mimics the principal relativistic effects and, contrary to the original "exact" formula, has low computational cost. Our model is appropriated for numerical simulations but not for precise ephemeris computations.