THE PULSATIONAL NATURE OF R-CORONAE-BOREALIS - LIGHT AND RADIAL-VELOCITY VARIATIONS DURING 1990 AND 1991

We report photometry and radial velocities of the R Coronae Borealis ( RCB) star R CrB, obtained during 1991. We compare these observations w ith published photometry obtained during 1990 and velocities obtained during 1990 and 1991, and analyse these data using Fourier techniques. In line with the conclusions of earlier analyses, the pulsational nat ure of R CrB is difficult to quantify, particularly on time-scales of longer than a year. The 1990 data are possibly consistent with the pre sence of a 43-d radial pulsation mode. During 1991 there was some evid ence for a periodicity near this value in the radial velocities, but n ot in the photometric data. Additional data are desirable to investiga te the possible presence of one or more periodicities in the light and radial velocity curves.