Strange hadronic stellar matter within the Brueckner-Bethe-Goldstone theory

In the framework of the non-relativistic Brueckner-Bethe-Goldstone theory, we derive a microscopic equation of state for asymmetric and $\beta$-stable matter containing ${\mathrm{\Sigma }}^{-}$ and $\mathrm{\Lambda }$ hyperons. We mainly study the effects of three-body forces (TBFs) among nucleons on the hyperon formation and the equation of state (EoS). We find that, when TBFs are included, the stellar core is almost equally populated by nucleons and hyperons. The resulting EoS, which turns out to be extremely soft, has been used in order to calculate the static structure of neutron stars. We obtain a value of the maximum mass of 1.26 solar masses (1 solar mass $M_o\simeq 1.99\cdot {10}^{33}g$). Stellar rotations increase this value by about 12%.