  We study several families of planar quadratic diffeomorphisms near a
Bogdanov-Takens bifurcation. For each family, the associate bifurcation diagram
can be deduced from the interpolating flow. However, a zone of chaos confined
between two lines of homoclinic bifurcation that are exponentially close to
one-another is observed. The goal of this paper is to test numerically an
accurate asymptotic expansion for the width of this chaotic zone for different
families.
