  Centaurus A is the closest radio-loud active galaxy. Very Long Baseline
Interferometry (VLBI) enables us to study the jet-counterjet system on
milliarcsecond (mas) scales, providing essential information for jet emission
and propagation models. We study the evolution of the central parsec jet
structure of Cen A over 3.5 years. The proper motion analysis of individual jet
components allows us to constrain jet formation and propagation and to test the
proposed correlation of increased high energy flux with jet ejection events.
Cen A is an exceptional laboratory for such detailed study as its proximity
translates to unrivaled linear resolution, where 1 mas corresponds to 0.018 pc.
The first 7 epochs of high-resolution TANAMI VLBI observations at 8 GHz of Cen
A are presented, resolving the jet on (sub-)mas scales. They show a
differential motion of the sub-pc scale jet with significantly higher component
speeds further downstream where the jet becomes optically thin. We determined
apparent component speeds within a range of 0.1c to 0.3c, as well as identified
long-term stable features. In combination with the jet-to-counterjet ratio we
can constrain the angle to the line of sight to ~12{\deg} to 45{\deg}. The high
resolution kinematics are best explained by a spine-sheath structure supported
by the downstream acceleration occurring where the jet becomes optically thin.
On top of the underlying, continuous flow, TANAMI observations clearly resolve
individual jet features. The flow appears to be interrupted by an obstacle
causing a local decrease in surface brightness and a circumfluent jet behavior.
We propose a jet-star interaction scenario to explain this appearance. The
comparison of jet ejection times with high X-ray flux phases yields a partial
overlap of the onset of the X-ray emission and increasing jet activity, but the
limited data do not support a robust correlation.
