, J. Alcolea
, R. Neri
, M. Grewing
Centro Astronómico de Yebes (IGN), Apartado 148, E-19080
Guadalajara, Spain 
IRAM, 300 rue de la Piscine, F-38406 St Martin d'Hères, France 
, a hollow prolate structure, with
an axial velocity increasing with the distance to the star up to about 60
kms
, and a central condensation with velocities smaller than 10 kms
. A
remarkable continuity in position and velocity is found between the hollow
component and the bipolar flow. We argue that these properties indicate
that an important dynamical interaction between both features is active at
the present moment and affects most of the nebular material. Such an
interaction would consist in a significant momentum transport from the
bipolar fast flow to the rest of the nebula.
Figure: Channel maps of the 
CO J=1--0 line from M1--92 taken with the PdB mm-interferometer.
Spatial units are offsets in arc seconds with respect to the position of the
central star (cross). North is top and East is left. LSR velocities are marked
in the upper left corner.
