Mirabel I.F., Claret A., Cesarsky C.J., Boulade O., Cesarsky D.A.
We report the discovery of warm dust in the surroundings of the compact high energy sources SS433 and Cygnus X-1. In the jets of SS433 we have observed the infrared counterpart of the brighter X-ray knot at a distance of 50pc from the compact source. The observation reported here suggests that dust formation takes place in the ejecta, and that their infrared luminosity exceeds their X-ray luminosity. In Cygnus X-1 we find that the compact source is surrounded by an infrared envelope of 0.2pc radius. We propose that besides a gaseous component, warm dust components contribute to the infrared emission from the extended envelope.