Triggering mixing and deceleration in FRI jets: a solution
  Since Fanaroff & Riley (1974) reported the morphological and brightness
dichotomy of radiogalaxies, and it became clear that the symmetric emission
from jets and counter-jets in the centre-brightened, less powerful, FRI sources
could be caused by jet deceleration, many works have addressed different
mechanisms that could cause this difference. Recent observational results seem
to indicate that the deceleration must be caused by the development of
small-scale instabilities that force mixing at the jet boundary. According to
these results, the mixing layer expands and propagates down to the jet axis
along several kiloparsecs, until it covers the whole jet cross-section. Several
candidate mechanisms have been proposed as the initial trigger for the
generation of such mixing layer. However, the instabilities proposed so far do
not fully manage to explain the observations of FRI jets and/or require a
triggering mechanism. Therefore, there is not still a satisfactory explanation
for the original cause of jet deceleration. In this letter, I show that the
penetration (and exit) of stars from jets could give the adequate explanation
by means of creating a jet-interstellar medium mixing layer that expands across
the jet.
