Fig. 2

Effects of varying specific heat capacity. a The effect of uncertainty in specific heat capacity on the range of possible asteroid radii and formation times for an Itokawa-like parent body. Each of the three curves shown is actually made up of three isothermal lines corresponding to Itokawa’s thermal constraints of having a peak temperature between 1073 and 1273 K and a central temperature greater than 973 K at 7.6 Ma, as in Figure 1. The solid black curve shows the original result, seen in Fig. 1. The dashed and dotted curves show the result when the specific heat capacity is increased or decreased, respectively. b, c Central temperature over time for two simulated bodies with end-member specific heat capacity values and formation time and radius values corresponding to the diamond markers on a. b A 21-km radius body formed at 1.78 Ma is able to narrowly avoid exceeding the maximum peak temperature constraint due to its greater heat capacity at 1.1 times the base value. c A 50-km body formed at 2.34 Ma scarcely fulfills the minimum peak temperature constraint due to its lower heat capacity at 0.9 times the base value