  We present transit observations of the WASP-2 exoplanet system by the Apache
Point Survey of Transit Lightcurves of Exoplanets (APOSTLE) program. Model
fitting to these data allows us to improve measurements of the hot-Jupiter
exoplanet WASP-2b and its orbital parameters by a factor of ~2 over prior
studies; we do not find evidence for transit depth variations. We do find
reduced chi^2 values greater than 1.0 in the observed minus computed transit
times. A sinusoidal fit to the residuals yields a timing semi-amplitude of 32
seconds and a period of 389 days. However, random rearrangements of the data
provide similar quality fits, and we cannot with certainty ascribe the timing
variations to mutual exoplanet interactions. This inconclusive result is
consistent with the lack of incontrovertible transit timing variations (TTVs)
observed in other hot-Jupiter systems. This outcome emphasizes that unique
recognition of TTVs requires dense sampling of the libration cycle (e.g.
continuous observations from space-based platforms). However, even in systems
observed with the Kepler spacecraft, there is a noted lack of transiting
companions and TTVs in hot-Jupiter systems. This result is more meaningful, and
indicates that hot-Jupiter systems, while they are easily observable from the
ground, do not appear to be currently configured in a manner favorable to the
detection of TTVs. The future of ground-based TTV studies may reside in
resolving secular trends, and/or implementation at extreme quality observing
sites to minimize atmospheric red noise.
