  A mean field calculation is carried out to obtain the equation of state (EoS)
of nuclear matter from a density dependent M3Y interaction (DDM3Y). The energy
per nucleon is minimized to obtain ground state of the symmetric nuclear matter
(SNM). The constants of density dependence of the effective interaction are
obtained by reproducing the saturation energy per nucleon and the saturation
density of SNM. The energy variation of the exchange potential is treated
properly in the negative energy domain of nuclear matter. The EoS of SNM, thus
obtained, is not only free from the superluminosity problem but also provides
excellent estimate of nuclear incompressibility. The EoS of asymmetric nuclear
matter is calculated by adding to the isoscalar part, the isovector component
of M3Y interaction. The SNM and pure neutron matter EoS are used to calculate
the nuclear symmetry energy which is found to be consistent with that extracted
from the isospin diffusion in heavy-ion collisions at intermediate energies.
The $\beta$ equilibrium proton fraction calculated from the symmetry energy and
related theoretical findings are consistent with the constraints derived from
the observations on compact stars.
