  We predict the polarization of Lambda and antiLambda hyperons in peripheral
heavy ion collisions at ultrarelativistic energy, based on the assumption of
local thermodynamical equilibrium at freeze-out. The polarization vector is
proportional to the curl of the inverse temperature four-vector field and its
length, of the order of percents, is maximal for particle with moderately high
momentum lying on the reaction plane. A selective measurement of these
particles could make Lambda polarization detectable.
