  We analyze the velocity gradient across the jets of the young stellar object
(YSO) NGC 1333 IRAS 4A2 and explain it by decomposing the two opposite jets to
two opposite sub-jets. The two sub-jets have the same radial velocity and the
angle between them is only several degrees. Each of the two sub-jets is
composed of two components. We also show that the alternative interpretation of
jets' rotation is unlikely to account for the velocity gradient. The two
sub-jets directions are constant, and there is no indication for precession.
The line connecting the centers of the sub-jets defines a preferred direction
in a plane parallel to the accretion disk launching the jets. We suggest that
the preferred constant direction in the accretion disk is determined by the
semi-major axis of a highly eccentric orbit of a brown dwarf or a massive
planet companion. At each periastron passage the companion perturbs the
accretion disk with a quadrupole mode, e.g., two spiral arms, that lead to the
launching of the two sub-jets. We predict that a careful monitoring of the
system will reveal a periodic activity with a period of few months to several
years.
