Breaching the Eddington Limit in the Most Massive, Most Luminous Stars

Stan Owocki (Univ. of Delaware) - Apr 14, 2008 at 12:10 pm

One of the most fundamental tenets in astronomy is the Eddington limit, at which the radiative force from electron scattering equals the binding force of gravity. Luminous Blue Variable (LBV) stars observed near this limit often show evidence of unstable episodes of extensive mass loss, with the most extreme example being the 1840-60 giant eruption of eta Carinae, which resulted in ejection of ca. 10 solar masses in a bipolar outflow seen today as the Homunculus nebula. This talk will discuss how a super-Eddington luminosity can lead to such extreme mass loss, through continuum driving moderated by the "porosity" associated with structure arising from instabilities in the star's envelope and atmosphere. I will emphasize the broad implications of such episodes of super-Eddington mass loss for setting the upper mass limit of stars, as well as for massive-star evolution, including progenitors of gamma-ray bursts, and even the first stars in the universe.

The seminar will be held in 544 Campbell Hall.


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