  In parabolic flight experiments we studied the wind induced erosion of
granular beds composed of spherical glass beads at low gravity and low ambient
pressure. Varying g-levels were set by centrifugal forces. Expanding existing
parameter sets to a pressure range between $p=300-1200\,$Pa and to g-levels of
$g=1.1-2.2\,\rm m\,s^{-2}$ erosion thresholds are still consistent with the
existing model for wind erosion on planetary surfaces by Shao & Lu (2000).
These parameters were the lowest values that could technically be reached by
the experiment. The experiments decrease the necessary range of extrapolation
of erosion thresholds from verified to currently still unknown values at the
conditions of planetesimals in protoplanetary discs. We apply our results to
the stability of planetesimals. In inner regions of protoplanetary discs,
pebble pile planetesimals below a certain size are not stable but will be
disassembled by a head wind.
