Infrared excesses of barium stars
A sample of thirty-one barium stars has been studied using JHKLMN photometry. Infrared excesses are found to occur in the H, M, and N bands. The H-excess appears to correlate with the barium intensity (defined by the abnormal strength of the 4554 Å BaII line), whereas the excesses in M and N do not. Two mechanisms are suggested for the production of these excesses: (1) redistribution of energy from the Bond-Neff optical depression into the infrared, and (2) thermal emission from residual material associated with mass transfer in a binary system. The correlation of the H-excess with suppressed optical flux is suggestive of energy redistribution, but the M- and N-excesses might indicate thermal energy from gas and dust.
KeywordsEnergy Redistribution Mass Transfer Event Radial Velocity Variable Infrared Excess Optical Flux
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