Observations of 101 Be stars taken over a two year period in the near-IR between 1 and 5 microns are presented and discussed. The near-IR color excess of all program stars is derived, and found to increase with wavelength for all these stars. The fraction of stars with color excess doubles between 1.25 and 3.6 microns. There appears to be an upper limit to the magnitude of the color excess as a function of stellar type, with early-type stars having a higher upper limit than later spectral types. No correlation of the presence or magnitude of color excess with projected rotational velocity is evident. The spectral index of the excess emission spectra is calculated for stars having color excess. On average, the spectral index through the near-IR and far-IR IRAS wavelength regimes is constant. There is evidence that some stars have excess emission with spectral index values outside the range expected for free-free and bound-free emission. This is attributed to either dust emission or the effect of absorption of photospheric emission by cool circumstellar material along the line of sight to the star.
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Dougherty et al. (1991) studied this question.
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