SIMBAD references

A preliminary report of the analysis of multicolor data obtained in February 1994 for AM CVn is presented. The light curve has been observed in the UBVRI passbands over three nights with 20 % coverage. Temporal spectroscopy of the data shows that the 525 and 350 s modulations of the light curve have amplitudes, phases and shapes which are identical in the UBVR filters. In the infrared passband, a possible phase shift with respect to other passbands is detected. The erratic 1011 s modulation is strong in our data, and shows a bigger amplitude in the U than in the BVRI filters. The phases and shapes of this period are however similar in all five passbands. The temperature-independent periods of 525 s and 350 s seem to confirm their origin in the apparent geometrical variation of AM CVn as an accreting binary system. The 1011 s period may originate from a hot region of the disk.