Trigonometric Parallaxes of Massive Star Forming Regions: G012.88+0.48
  and W33
  We report trigonometric parallaxes for water masers in the G012.88+0.48
region and in the massive star forming complex W33 (containing G012.68--0.18,
G012.81--0.19, G012.90--0.24, G012.90--0.26), from the Bar and Spiral Structure
Legacy (BeSSeL) survey using the Very Long Baseline Array. The parallax
distances to all these masers are consistent with $2.40^{+0.17}_{-0.15}$ kpc,
which locates the W33 complex and G012.88+0.48 in the Scutum spiral arm. Our
results show that W33 is a single star forming complex at about two-thirds the
kinematic distance of 3.7 kpc. The luminosity and mass of this region, based on
the kinematic distance, have therefore been overestimated by more than a factor
of two. The spectral types in the star cluster in W33\,Main have to be changed
by 1.5 points to later types.
