A Case against a Significant Detection of Precession in the Galactic
  Warp
  Recent studies of warp kinematics using Gaia DR2 data have produced
detections of warp precession for the first time, which greatly exceeds
theoretical predictions of models. However, this detection assumes a warp model
derived for a young population (few tens of megayears) to fit velocities of an
average older stellar population of the thin disk (several gigayears) in
Gaia-DR2 observations, which may lead to unaccounted systematic errors. Here,
we recalculate the warp precession with the same approach and Gaia DR2
kinematic data, but using different warp parameters based on the fit of star
counts of the Gaia DR2 sample, which has a much lower warp amplitude than the
young population. When we take into account this variation of the warp
amplitude with the age of the population, we find that there is no need for
precession. We find the value of warp precession $\beta = 4^{+6}_{-4}$ km
s$^{-1}$ kpc$^{-1}$, which does not exclude nonprecessing warp.
