Abstract:
We have searched the IRAS Polar Stratospheric Clouds (PSC) for dust shells around A-F supergiant stars similar to the high galactic latitude A-F supergiants with circumstellar dust shells. We have found that HD 114855 (F5Ia), HD 158616 (F8I), SAO 173329 (F51), V718 Sco (A8III), HD 53300 (A0Ib), HD 331319 (F3Ib), SAO 40039 (A4Ia) to be IRAS sources with far infrared colors and flux distribution similar to those of planetary nebulae. These stars have detached cold dust shells. Temperatures, masses, radii and luminosities of the dust shells are derived. The dust shell characteristics suggest that these stars have suffered severe mass loss in the recent past during their asymptotic giant branch (AGB) stage of evolution. Their present position in the H-R diagram suggests that they are evolving towards left into the region of planetary nebulae
