  We conduct 2D numerical simulations of jets expanding into the slow wind of
asymptotic giant branch stars. We show that the post-shock jets' material can
explain the observed extended X-ray emission from some planetary nebulae (PNs).
Such jets are thought to shape many PNs, and therefore it is expected that this
process will contribute to the X-ray emission from some PNs. In other PNs (not
simulated in this work) the source of the extended X-ray emission is the
shocked spherical wind blown by the central star. In a small fraction of PNs
both sources might contribute, and a two-temperatures gas will fit better the
X-ray properties than a one-temperature gas. A spacial separation between these
two components is expected.
