Mass–radius relation and mass surface density distribution for the core sample. Left panel: core masses as a function of estimated radius. Solid gold lines represent different values of core surface density: from bottom to top, 0.1, 1, 10, and 100 g cm⁻², respectively. Percentages of data points within the corresponding bins of surface density are given in grey. Red points indicate the median M_core values in given bins (red bars) of R_core . The solid blue line is the best fit to the data points, corresponding to the power-law relation reported in the top-left corner. Right panel: distribution of the mass surface density of the cores. The vertical dashed black line marks the median value of 1.7 g cm⁻².