High Mass Loss Events -- Giant Eruptions (Supernova Impostors), Luminous Blue Variables, and Hypergiants


It has become increasingly apparent in the past decade or more that evolved massive stars, those with initial masses above 20Msun or so experience high mass loss episodes before their end state whether as a true supernova or collapsing to a black hole. These high mass loss events determine the appearance of the upper HR Diagram, see Humphreys and Davidson 1979, 1994 [,]. The mass loss may take different forms, occur in different types of stars, and may be driven by different physical processes.