ASCA OBSERVATIONS OF U-GEMINORUM DURING QUIESCENCE

ASCA observations of the dwarf nova U Gem separated by 3 weeks during a long quiescent interval show no noticeable differences in count rate s nor in the relatively hard (7-10 keV) X-ray spectrum. However, there are orbital phase-dependent variations in the quiescent X-ray light c urves, which are similar to the absorption dips previously reported du ring outburst and decline from outburst. The dips are only apparent at low energies, and the different structure of the light curves indicat es changes in the absorbing material between the two observations. The se results imply that the X-ray emission at quiescence must be confine d to a small area and that absorbing material must be located at very stable positions far out from the orbital plane.