DOPPLER TOMOGRAPHY OF THE X-RAY TRANSIENT J0422-OUTBURST(32 DURING THE 1993 DECEMBER MINI)

Intermediate-resolution optical spectra of the X-ray transient J0422 32, obtained during the 1993 December mini-outburst, show a strong mo dulation in radial velocities and equivalent widths of all the emissio n lines, with a period of 0.2127+/-0.0013 d (5.1 h). This modulation i s in good agreement with the photometric period of 0.2121 d reported d uring both this and the original outburst. In particular, the complex Heir lambda 4686 emission profile displays an intense S-wave with a ve locity semi-amplitude of similar to 755 km s(-1). We discuss the impli cations of this emission originating either in the hotspot or on the h eated face of the companion star. In the first case a mass function f( M) similar to 1.2 M. is implied, whereas in the latter case f(M) simil ar to 9.5 M..