BVRI PHOTOMETRY OF THE EXTRINSIC S-STAR HR-1105

BVRI photometry of the extrinsic S star HR 1105 shows a stable periodi c light variability with a period of 24.76 days superimposed upon long term changes presumably related to the orbital period. The variations are in phase for all four magnitudes with the amplitude of this varia bility being about the same for B and V, but smaller for R and even sm aller for I. As the primary is a M3 III star, these brightness changes are mostly likely due to the pulsation of the primary star.