SDSS J161033.64-010223.3: a second cataclysmic variable with a non-radially pulsating primary

We find from high-speed photometry of the Sloan Digital Sky Survey cataclysmic variable candidate SDSS J161033.64-010223.3 that it has a double-humped modulation, which is probably orbital, with a period of 80.52 min, and shows strong ZZ Cet type pulsations. The largest amplitude oscillations have periods near 607, 345, 304 and 221 s. The amplitudes of some of the oscillations are seen to vary on time-scales of hours, indicating modes with unresolved multiplets in which the splittings are similar to1 d(-1). This is only the second dwarf nova found to have non-radial pulsations of its white dwarf primary.