  We study pion and kaon condensation using three-flavor chiral perturbation
theory at finite isospin and strangeness quark chemical potentials {\mu}I and
{\mu}S . The phase diagram consists of a vacuum phase and three distinct Bose
condensed phases with condensates of charged pions as well as charged and
neutral kaons. Adding electromagnetic interactions, a phase with a charged
condensate becomes a Higgs phase and the resulting phase diagram is modified
due to the electromagnetic mass splittings of the mesons. The results for the
pion-condensed phase are applied to calculate mass-radius relation of pion
stars. Local electric charge neutrality is imposed by adding electrons, muons
together with their neutrionos. Finally, we compare our results for the
mass-radius relations with those from recent lattice simulations, and find very
good agreement.
