NEAR-QUIESCENT PHOTOMETRY OF THE X-RAY TRANSIENT J0422+32

We present I-band photometry of the soft X-ray transient (SXT) J0422 32 taken during a low-brightness state over two weeks in 1993 October , The object had a mean V magnitude of 19.9, approximately 2 mag above its subsequent, presumably quiescent, level of V similar to 22.4. The se data revealed a periodicity at 16.18 h (significance level >99 per cent), but we could find no evidence for the previously reported 5.1-h period. We cannot account for the physical origin of this 16-h modula tion, but suspect that it is related to the brightness state of J0422 + 32. We show that it cannot be an ellipsoidal effect, as the secondar y star would be much brighter than the current minimum. The 5.1-h peri od could be orbital, with a very late-type (similar to MO-M5) secondar y which is too faint to be observable if the distance is greater than or equal to 1 kpc.