Raffaella Margutti edited untitled.tex  over 8 years ago

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\section{Steady vs Eruptive Massloss}  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 as a function of time before explosion.    The mass loss rates during the last few hundred years of evolution of some core collapse supernova progenitors seem to violate the maximum values allowed by line-driven winds \citep[$\dot{M} \sim 10^{-4}$M$_\odot$yr$^{-1}$][]{Smith_2006}.   %($\dot{M} ($\dot{M}  \sim 10^{-4}$M$_\odot$yr$^{-1}$, \citet{Smith_2006}, \cite{Smith_2006},  see also Fig.~\ref{fig}). Intense stellar mass loss during the final years before core collapse could be caused by   internal gravity waves excited by core convection during Neon and Oxygen fusion \cite{Quataert_2012}. This mechanism is able to explain mass loss rates of $\sim 0.01 − 1 $M$_\odot$yr$^{-1}$ and velocities of $\sim 200 − 500$ km s$^{-1}$ (Quataert et al. 2015). Most importantly, the model predicts a correlation between the energy associated with pre-SN mass ejection and the time to core collapse, with the most intense mass loss preferentially occurring closer to core collapse \cite{Shiode_2013}.