  The eastern region of the calcium isotope chain of the nuclei chart is,
nowadays, of great activity. The experimental assessment of the limit of
stability is of interest to confirm or improve microscopic theoretical models.
The goal of this work is to provide the drip line of the calcium isotopes from
the exact solution of the pairing Hamiltonian which incorporates explicitly the
correlations with the continuum spectrum of energy. The modified Richardson
equations, which include correlations with the continuum spectrum of energy
modeled by the continuum single particle level density, is used to solve the
many-body system. Three models are used, two isospin independent models with
core 40Ca and 48Ca, and one isospin dependent model. One and two-neutron
separation energies and occupation probabilities for bound and continuum states
are calculated from the solution of the Richardson equations. The one particle
drip line is found at the nucleus 57Ca, while the two neutron drip line is
found at the nucleus 60Ca from the isospin independent model and at 66Ca from
the isospin dependent one.
