deletions | additions       diff --git a/soundspeed.tex b/soundspeed.tex  index 62d1c7f..a260b80 100644  --- a/soundspeed.tex  +++ b/soundspeed.tex 
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\subsubsection{Sound speed}  Observations of jets and winds from CTTS indicate that typical temperatures are a few thousand K (except in shocked regions)  and typical densities are in the range $10^4-10^6 \mathrm{ cm}^{-3}$ in the optically visible component \citep[e.g.][]{2000A&A...356L..41L,2007ApJ...657..897K}. This might not be the same outflow component that our model describes, but it is the best available observational estimate available. With those numbers the sound speed $c_s$ is \begin{equation}  c_s=\sqrt{\gamma \frac{k T}{m_{\textrm{H}}} \approx 10 \textrm{ km s}^{-1} \; ,  \end{equation}