  Recently, differences in Doppler shifts across the base of four close
classical T Tauri star jets have been detected with the HST in optical and
near-ultraviolet (NUV) emission lines, and these Doppler shifts were
interpreted as rotation signatures under the assumption of steady state flow.
To support this interpretation, it is necessary that the underlying disks
rotate in the same sense. Agreement between disk rotation and jet rotation
determined from optical lines has been verified in two cases and rejected in
one case. Meanwhile, the NUV lines, which may trace faster and more collimated
inner spines of the jet than optical lines, either agree or show no clear
indication. We propose to perform this test on the fourth system, Th 28. We
present ALMA high angular resolution Band 7 continuum, 12CO(3-2) and 13CO(2-1)
observations of the circumstellar disk around the T Tauri star Th 28. We were
able to detect, in CO and continuum, clear signatures of a disk in Keplerian
rotation around Th28. The 12CO emission is resolved, allowing us to derive
estimates of disk position angle and inclination. The large velocity separation
of the peaks in 12CO, combined with the resolved extent of the emission,
indicate a central stellar mass in the range 1-2 Msun. The rotation sense of
the disk is well detected in both 13CO and 12CO emission lines, and this
direction is opposite to that implied by the transverse Doppler shifts measured
in the optical lines of the jet. The Th 28 system is the second system where
counter-rotation between the disk and the optical jet is detected. These
findings imply either that optical transverse velocity gradients detected with
HST do not trace jet rotation or that modeling the flow with the steady
assumption is not valid. In both cases jet rotation studies that rely solely on
optical lines are not suitable to derive the launching radius of the jet.
