THE VARIABILITY OF THE R-CORONAE-BOREALIS STAR UX ANTLIAE AT MAXIMUM LIGHT

Broad-band photometry obtained during 1990-1993 and radial velocities measured during 1991 are reported for the little-studied R Coronae Bor ealis (RCB) star UX Antliae. Photometrically, the star exhibits irregu lar and low-amplitude (0.1-0.3 mag) variations on time-scales of 40-50 d, typical in this respect to many other RCB stars with T-eff approxi mate to 7000 K. (Spectroscopically, UX Ant is similar to other 'F-type ' RCB stars such as R CrB and RY Sgr.) A short series of velocity meas urements did not indicate radial velocity variability (sigma = 1.9 km s(-1)). These results are compared to the pulsation properties of othe r RCB stars. Finally, UX Ant is shown to have a weaker infrared excess than other RCB stars, probably due to the recent low occurrence of de clines in this object.