Properties of the optical 2-second oscillations in E1405-451

The AM Her type system E1405-451 is known to show 1–3 second variability in its optical emission. Our observations show this variability to be due to quasi-periodic oscillations with a coherence time on the order of one minute. The observations also reveal variations in the color of the oscillating light source. These variations are difficult to explain with present cyclotron emission models.Based on observations obtained at the European Southern Observatory, La Silla, Chile.Paper presented at the IAU Colloquium No. 93 on Cataclysmic Variables. Recent Multi-Frequency Observations and Theoretical Developments, held at Dr. Remeis-Sternwarte Bamberg, F.R.G., 16–19 June, 1986.