Cumulative number of meteoroids (ordinate) with a surface layer depth equal to or greater than h/R (abscissa), where R is the radius of the body. The data on the ordinate are given in percents of the total population initially released along the orbit of the stream. The spin axes were assumed to be isotropic and three sizes of meteoroids were used: (i) D = 10 cm (solid line); (ii) D = 1 cm (dotted line); and (iii) D = 1 mm (dashed line). When the dotted or dashed lines are not plotted, no insulating surface layer develops; ten-centimetre size meteoroids of the Southern δ-Aquariids stream (top and left panels) are all destroyed by the thermal stresses. Meteoroid showers, denoted by the IAU three-letter code, are SDA for Southern δ-Aquariids, GEM for Geminids, MON for Monocerotids, NTA for Northern Taurids, AMO for α-Monocerotids, ETA for η-Aquariids, CAP for α-Capricornids and DRA for (Oct.) Draconids. The panels from top to down and left to right are ordered according to the increasing perihelion distance, i.e., smallest for the Southern δ-Aquariids (top and left panel) and largest for the (Oct.) Draconids (bottom and right panel).