SIMBAD references

We present the analysis of infrared photometry and millimeter spectroscopy of a sample of 74 late-type supergiants. These observations are particularly suitable to study the mass loss and the circumstellar envelopes of evolved massive stars. In particular, we quantify the circumstellar infrared excess, the relation of mass loss with stellar properties, using the K-[12] colour index as mass-loss indicator. We do not find any clear correlation between mass loss rate and luminosity. We also show that the K-band magnitude is a simple luminosity indicator, because of the relative constancy of the K-band bolometric correction.