The dwarf nova PQ andromedae

Joseph Patterson, Columbia University
John R. Thorstensen, Dartmouth College
Eve Armstrong, Columbia University
Arne A. Henden, Universities Space Research Association
Robert I. Hynes, Louisiana State University


We report a photometric study of the WZ Sagittae-type dwarf nova PQ Andromedae. The light curve shows strong (0.05 mag full amplitude) signals with periods of 1263(1) and 634(1) s, and a likely double-humped signal with P = 80.6(2) minutes. We interpret the first two as nonradial pulsation periods of the underlying white dwarf, and the last as the orbital period of the underlying binary. We estimate a distance of 150(50) pc from proper motions and the two standard candles available: the white dwarf and the dwarf-nova outburst. At this distance, the K magnitude implies that the secondary is probably fainter than any star on the main sequence-indicating a mass below the Kumar limit at 0.075 M⊙. PQ And may be another "period bouncer," where evolution now drives the binary out to a longer period. © 2005. The Astronomical Society of the Pacific. All rights reserved.