The Infrared And Optical Pulsations Of G29-38

High-speed infrared photometry at 1.25, 2.2, and 3.5-mu-m of the pulsating white dwarf G29-38 reveals the presence of unexpectedly large amplitude signals at 2.2-mu-m, with periods of 186, 243, and 268 s. Simultaneous optical coverage demonstrates the presence of signals of identical period and phase in blue light, which proves that they are ultimately seated in the white dwarf, not in the cool component known to be present in the system. But their anomalously high amplitude in the infrared suggests either a breakdown of stellar atmosphere theory or a process by which the pulsating white dwarf can very efficiently excite an oscillation in the cool component. We discuss a model in which a dusty ring reprocesses the incident radiation from the white dwarf, assumed to contain both east-west and north-south pulsations. The model has some heuristic value but requires a very special geometry to satisfy the observations.We also use our pulse timings to study the long-term phase residuals of the dominant 615 s optical pulsation. The results do not support the idea that the phase residuals are periodic.