  The exterior gravitational fields of the massive Schwarzschild, Kerr and NUT
particles have an algebraic type {\bfseries D} according to Petrov's algebraic
classification of the gravitational fields. A lightlike limit is input for
these particles. It is shown that under this limiting procedure the
gravitational fields of the particles are transformed into the gravitational
fields of the lightlike particles a lighton and a helixon. On the other hand
this limit can be described as a cusp catastrophe on a level of Weyl's matrix
with a change of a gravitational field symmetry of such sources. In considered
cases we have a phase gravitational transition of second kind from {\bfseries
D} type into {\bfseries N} type or {\bfseries III} type. There is a transition
of one "phase" to another. Petrov's algebraic types are the different "phases"
of the gravitational field. It is shown that the lightlike sources in General
Relativity "have no hairs".
