Brian Espey, Trinity College Dublin
"Understanding Mass Loss in Evolved Stars Like the Sun"

Abstract:
Although supernovae are the showiest examples of stellar death, and explosively seed the interstellar medium, their progenitor stars comprise only a small fraction of the total stellar population. As a result, the bulk of interstellar material - including the important common elements carbon, nitrogen and oxygen - comes from stars similar in mass to our own Sun. At the end of its life, our own Sun will expand and become a red giant, and will cede its outer layers to space in the form of a wind. Unfortunately, although we can see the end result of this process in the form of planetary nebulae and interstellar material, we still know very little about how red-giant winds get started and how they are driven. I will report on recent results from a number of systems where we can use multi-wavelength diagnostics from both space and ground spanning the far ultraviolet to the infrared and radio in order to understand the wind phenomenon. Interestingly, although the stars we have examined differ in mass, radius, temperature and chemical abundance, the outflows bear striking similaries, aside from a scale factor to account for differences in mass loss. I shall review the results, and indicate the direction of future work.

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