Miras, Mass Loss, and the Ultimate Fate of the Earth (Abstract)

Volume 44 number 2 (2016)

Lee Anne Willson

Department of Physics and Astronomy, Iowa State University, Ames, IA 50011; lwillson@iastate.edu

Abstract

(Abstract only) The broad category of pulsating red giants includes semi-regular variables and Mira variables. The Miras are distinguished by their large amplitude variation in visible light, late spectral types (cool atmospheres), and the presence of emission lines during part of the cycle. The emission lines result from shock waves generated by pulsation that traverse their atmospheres. These stars’ atmosphere are often dusty, an indication of mass loss. Based on decades of detailed modeling we can recognize that the Mira stage corresponds to the onset of devastating mass loss, a process that removes most of the remaining envelope and reveals the degenerate core, a new white dwarf star. I’ll review the evidence for this claim, and then examine the effects of Mira stage mass loss on the future solar system. Finally, I shall draw some very general conclusions about the ultimate fate of the Earth.