Jeremiah edited section_Free_flow_thoughts_begin__.tex  over 8 years ago

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\section{Free flow thoughts}  \begin{itemize}  \item Intro:  \begin{itemize}  \item  Mass-loss is an important process in stellar evolution, especially for massive stars. \item It can determine the fate of a massive star: very little mass loss, and the star will explode as a red supergiant producing a SN II-P, but with significant mass-loss the hydrogen and even helium layers may be stripped entirely producing a SN Ic. \item Despite its importance theoretical considerations give us little insight into mass-loss expectations. \item Radiation driven winds certainly play a role, but they are not enough to explain the prevalence of stripped cores. \item Binary evolution may play a role, but the theory is not certain enough to predict mass-loss with reliability \item Complicating the picture even further, it's becoming clear that eruptive mass-loss may play a very important role in some stars. \item Although there are several possible mechanisms for mass-loss, we do not know when each dominates or even which one dominates. \item To help constrain mass-loss theory, we first need to understand the mass-loss history of massive stars. In particular, we need to know the mass-loss rate ($\dot{M}$) and velocity ($v$) as a function of time before explosion.  \end{itemize}  \item The late-time variability of radio emission from SNe can provide the mass-loss history history.  \item A record of the star's mass-loss history is imprinted in the circumstellar medium. If one knew the density profile and velocity profile of the CSM, then one can straightforwardly infer the mass-loss history.  \item Once the star explodes, the supernova shock quickly overtakes the pre-explosion ejecta, emitting synchrotron emission along the way. The variability in the synchrotron emission reflects the variability in the CSM density profile. Therefore, the shock acts as a CAT scan of the CSM, thereby providing the mass-loss history of the star. \item Our ambitious goal is to observe the radio variability for SN Ic, infer the mass-loss history, and put this mass-loss history in the context of stellar evolution theory.  \end{itemize}