Long-term VRI photometry of rho Cassiopeiae

We report over 5700 days (15 years) of VRI photometry of the yellow hypergi ant variable star rho Cassiopeiae. The V-I color curve is generally in phas e with the V light curve on timescales of a few hundred days, but there is a 4000 day variation in V-I which is absent from the light curve. The appro ximate ratio of Delta(V-I)/Delta V is 0.46. The most conspicuous period in the light curve, in the autocorrelation diagram, and in the power spectrum is about 820 days. Less significant periods of 380, 510, and 645 days also appear in the power spectrum, and there are many subcycles in the light cur ve with lengths of 200-500 days. Since the most recent comprehensive analys is of the light curve of rho Cas found a dominant period of 300 days, we co nclude that the behavior of the star is quite variable with time.