R66 (Aeq), an LMC B Supergiant with a Massive, Cool and Dusty Wind

The LMC's peculiar emission line star R 66 (Aeq) is studied by means of high dispersion spectroscopy and UBV and JHKLM photometry, from which a model is derived which consists of a massive, luminous B-type supergiant surrounded by a dense, cool expanding envelope and a circumstellar dust shell whose temperature is 1100 K at its inner edge. R 66 belongs to the massive post main sequence envelope objects characterized by drastic mass loss rates. Although it has not exhibited any variations, R 66 has many features in common with the S Dor variables during maximum phase. It is theorized that massive stars may spend 20 percent of their B supergiant evolutionary phase as drastic mass losers.