A Representative Sample of Be Stars IV : Infrared Photometry and the Continuum Excess

We present infra-red (JHK) photometry of 52 isolated Be stars of spectral types O9–B9 and luminos-ity classes III–V. We describe a new method of reduction, enabling separation of interstellar reddening and circum-stellar excess. Using this technique we find that the disc emission makes a maximum contribution to the optical (B − V) colour of a few tenths of a magnitude. We find strong correlations between a range of emission lines (Hα, Brγ, Br11, and Br18) from the Be stars' discs, and the cir-cumstellar continuum excesses. We also find that stellar rotation and disc excess are correlated.