Asymmetric supernova explosions and the formation of short period low-massX-ray binaries

We consider the formation of short period low-mass X-ray binaries using sta ndard evolutionary scenario which involves a common envelope phase and a su pernova explosion. We consider three models of systems and assume several v alues of the efficiency factor for the common envelope evolution (alpha(CE) ). In most cases the systems can only be formed if the neutron stars in the systems receive a kick velocity at their birth. We determine the lower and upper limits of the required kick velocity as a function of alpha(CE). Lar ger kicks are required to form shorter orbital period systems. Higher alpha (CE) also requires larger kicks. In general, the required kick velocity is of the order of a few hundred kms(-1) with a maximum of similar to 1000 kms (-1). The range of the required kick velocity is narrower for higher alpha( CE).