  Evolving the size distribution of solid aggregates challenges simulations of
young stellar objects. Among other difficulties, generic formulae for stability
conditions of explicit solvers provide severe constrains when integrating the
coagulation equation for astrophysical objects. Recent numerical experiments
have recently reported that these generic conditions may be much too stringent.
By analysing the coagulation equation in the Laplace space, we explain why this
is indeed the case and provide a novel stability condition which avoids time
over-sampling.
