  The edge-on debris disk of the nearby young star Beta Pictoris shows an
unusual brightness asymmetry in the form of a clump. The clump has been
detected in both the mid-IR and CO and its origin has so far remained
uncertain. Here we present new mid-IR observations of Beta Pic to track any
motion of the dust clump. Together with previous observations, the data span a
period of 12 years. We measured any projected displacement of the dust clump
over the 12-yr period to be $0.2^{+1.3}_{-1.4}$ au away from the star based on
the median and 1$\sigma$ uncertainty, and constrain this displacement to be <11
au at the 3$\sigma$ level. This implies that the observed motion is
incompatible with Keplerian motion at the 2.8$\sigma$ level. It has been
posited that a planet migrating outwards may trap planetesimals into a 2:1
resonance, resulting in the observed clump at pericentre of their orbits that
trails the planet. The observed motion is also incompatible with such resonant
motion at the 2.6$\sigma$ level. While Keplerian motion and resonant motion is
still possible, the data suggest that the dust clump is more likely stationary.
Such a stationary dust clump could originate from the collision or tidal
disruption of a planet-sized body, or from secular perturbations due to a
planet that create regions with enhanced densities in the disk.
