Mass of cores versus their separation in I18308. Blue filled circles represent observed cores. The dotted and solid black lines and the shaded regions are plotted following the outlines described in Wang et al. (2014) and Xu et al. (2023). The dotted black line corresponds to thermal Jeans fragmentation at T = 17.5 K and n = [10², 10⁸] cm^-3. The red shaded region was made with the same density range, but for T = [10, 30] K. The solid black line corresponds to turbulent Jeans fragmentation at σ_tot = 0.78 km s^-1 and n = [10²,10⁸] cm^-3. The green shaded region was made with the same density, but at σ_tot = [0.50,1.10] km s^-1. Vertical blue dashed lines indicate a typical observed core separation of 0.06 pc. Red and orange vertical dashed lines shows the predicted separation for thermal and turbulent Jeans fragmentation models, respectively. Mass sensitivity and spatial sensitivity of ALMA 1.3 mm observations are shown as the orange shaded bands.