We report the discovery of a new molecular hydrogen outflow in the Ser
pens molecular cloud. Narrowband filter images taken in the 2.12 mu m
v = 1-0 S(1) transition of H-2 and adjacent continuum reveal a series
of bright knots of pure line emission apparently emerging to the north
-northwest from the embedded source SMM-3 and passing close to the vis
ible star CK-8. Low-resolution H-and K-band spectra of the region show
more than a dozen distinct H-2 transitions, whose strength ratios poi
nt to shock heating with T-exc similar to 2000 K. Echelle spectra of t
he S(1) transition with 20 km s(-1) resolution reveal unusual kinemati
cs: the line center velocity increases linearly with distance to the n
orth-northwest from SMM-3 until the bright knots of emission, at which
point the velocity begins dropping to a fraction of its maximum value
. The molecular hydrogen emission likely arises in limb-brightened bow
shocks as a jet from SMM-3 encounters the ambient molecular cloud. Th
is scenario is strengthened by recent HCO+ and SiO submillimeter obser
vations of SMM-3, which show an apparent outflow corresponding to the
H-2 structures.