Figure 18

Figure 18: Effects of a finite entropy of donors on the properties of AM CVn-stars. The left panel shows the relation between Porb and M˙ along tracks for a system with initial masses of components 0.2 M ⊙ and 0.6 M ⊙ (like in Figure 9). The solid lines show the evolution for donors with Tc = 104 K, 106 K, 5 × 106 K, and 107 K (left to right). The symbols show the positions of models with M2 = 0.01 M ⊙ (triangles), 0.02 M ⊙ (squares), and 0.05M ⊙ (pentagons). The disk stability criteria (for q = 0.05) are shown by the dashed lines (after [406]). The right panel compares the numbers of systems as a function of Porb for the model with a T = 0 WD (dot-dashed line) and the model with “realistic” cooling (solid lines, RWDC). The smooth curves show the percentage of each population laying above a given Porb. (Figures from [77].)