Example evolutionary track for the formation of the WD−BD binary SDSS J1411+2009. The binary consists of two stars orbiting each other, with initial masses of 1.68 M_⊙ and 0.050 M_⊙ and an initial orbital period of 445 days. The evolution of the stellar radius and orbital separation is shown in the top panel, the evolution of the stellar mass, core mass, and orbital period is shown in the middle panel, and the stellar type evolution of the primary star is shown in the bottom panel.