High sensitivity observations of H92a and He92a Radio Recombination Lines
and continuum emission were made toward three positions in the Rosette
Nebula. A possible detection of He at such high frequency is reported, at
least in one position. Present results are considered together with
previous ones to look for correlation between some physical parameters and
the quantum number (n). A non-LTE model is proposed which can describe the
dependence of line contrast, Te, line width and line radial velocity on n.
There is evidence of an unusually sharp decreasing of RRL radial
velocity with n. The following scenario may then be proposed: a stellar
wind comes in contact with the outer surrounding dense material; the
corresponding shock forms a jet.