Astronomy and astrophysics vol:293 issue:2 pages:363-370
The A2 supergiant 3 Puppis is surrounded by circumstellar gas, as is attested by the double-peaked emission displayed by the Ha: lines, the NaID lines and the lines of [OI]. In addition, a large infrared excess due to dust in a disk is observed. The presence of circumstellar dust around an A-supergiant is unusual, and has led to the suggestion that 3 Puppis is not a massive supergiant, but rather an evolved low-mass object in transition between the AGB-phase and the planetary nebula phase. However, the photometric and spectroscopic data provide convincing arguments to conclude that 3 Puppis is a genuine massive supergiant.