VISUAL VERSUS NEAR-INFRARED VARIABILITY OF R-FOR - EVIDENCE FOR A MULTIPERIODIC CIRCUMSTELLAR MODULATION

Long-term AAVSO visual observations and near-infrared data on the carb on-rich long-period variable star R For have been analyzed. We find th at the Fourier development of the light curve depends on the observati on wavelength. For most components-including the main one-the amplitud e decreases from the visible to the near-infrared. The most sensitive components to the band correspond or are related to frequencies that a re close to subharmonics of the main periodicity. We propose that this may be the result of a multiperiodic modulation of the light curves d ue to circumstellar dust shells, as predicted by theoretical models. ( C) 1996 American Astronomical Society.