Luminous Blue Variable Stars

Examples include etaCar, PCyg, SDor.

Luminous Blue Variable (LBV) Stars are very massive, hot supergiants. They are unstable and variable, with irregular mass ejections. A mass loss episode increases the brightness. A cool (8000-9000K) shell forms around the star, with optical spectra showing an A-type supergiant with shell. In quiescence, the hot (20,000-25,000K) stellar photosphere is revealed, yielding a spectra of an O-B supergiant, with H, He, Fe, and [Fe] emission.

LBV Stars

PCyg (B2pe) x