Semi-major axis of planetary orbits versus the surface gravity (log g) of the host stars using the database of exoplanets.org (Han et al. 2014) and of NASA Exoplanet Archive (Akeson et al. 2013). The colours enable us to have an indication of the mass of the planet, while the size of the symbols are related to the mass of the star. The thick lines in the upper left corner show the minimum semi-major axis for survival of the planet as computed in the present work for stars with Ω_ini/ Ω_crit = 0.10. The case for Ω_ini/ Ω_crit = 0.50 would be barely distinguishable. These lines are labelled by the masses of the planet and of the star considered.