Near infra-red magnitudes of 248 early-type emission-line stars and related objects.

Nearly 250 early-type emission-line stars have been observed in the near infrared; approximately two thirds of these are found to exhibit excess radiation at these wavelengths. Two distinct mechanisms may contribute to the infra-red excesses: thermal radiation from circumstellar dust, and electron bremsstrahlung originating in a shell of ionized gas. it is not currently possible to distinguish between these two alternatives using infra-red photometry alone.