SIMBAD references

CCD observations for 10 (six previously known and four newly discovered) of the 11 RR Lyrae variables in NGC 5897 have been analyzed. The period-luminosity and period-amplitude plots indicate that the population of RR Lyrae variables in NGC 5897 includes three fundamental mode, four first-overtone and four second-overtone variables with mean periods 0.828, 0.459, and 0.343 days, respectively. The variables have properties similar to some of the Oosterhoff type II variables in ω Centauri. Two of the new variables (V11 and V13) were previously considered to be possible nonvariables that lie within or near the instability strip on the horizontal branch; both have V amplitudes less than 0.2 mag. There is a chance that one or two of the variables (V10 and possibly V3) might be anomalous Cepheids and not RR Lyrae stars.