\documentclass[tikz]{standalone}

\begin{document}

\begin{tikzpicture}
    \draw[->,thick] (-0.5,0.5) -- (9,0.5) node[right] {$\rho$};
    \draw[->,thick] (0,-4.5) -- (0,1.5) node[above] {$f(T,\rho)$};

    \draw[thick, domain=0.6:8.5, smooth] plot (\x, {-2.282*(1.3*(\x-0.6))+0.926*(1.3*(\x-0.6))^2-0.153*(1.3*(\x-0.6))^3+0.0081*(1.3*(\x-0.6))^4});
    \draw[dashed,thick] (1.8,-1.84) -- (6.7,-4.12);
    \node[above] at (8.2,-1.3) {$T<T_c$};

    \draw[dotted,thick] (1.8,-1.84) -- (1.8,0.5) node[above] {$\rho_{\mathrm{vap}}$};
    \draw[dotted,thick] (6.7,-4.12) -- (6.7,0.5) node[above] {$\rho_{\mathrm{liq}}$};

\end{tikzpicture}

\end{document}
