TRACING THE ROOTS OF INTERSTELLAR MID INFRARED-EMISSION

An attempt is made to link components of the interstellar extinction c urve to mid infrared emission of interstellar dust. The IRAS mid-infra red emission has been sought for in the direction to all early type st ars for which IUE extinction curves have been published. In 44 lines o f sight we were able to obtain well defined colours. By comparing the extinction curve components with these IRAS colours, we find that the bump in the extinction curve at 0.218 mum, and not the linear rise or FUV non-linear rise, is systematically weakened in lines of sight wher e the mid-infrared (12 micron) emitters have been removed.