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We fit an isothermal oscillatory density model to the outer disk of TW Hya inwhich planets have presumably already formed and they are orbiting within fourobserved dark gaps. At first sight, this 52 AU small disk does not appear to besimilar to our solar nebula; it shows several physical properties comparable tothose in HL Tau (size $R_{\rm max}=102$ AU) and very few similarities to AS 209($R_{\rm max}=144$ AU). We find a power-law density profile with index $k=-0.2$(radial densities $\rho(R) \propto R^{-1.2}$) and centrifugal support againstself-gravity so small that it virtually guarantees dynamical stability formillions of years of evolution to come. Compared to HL Tau, the scale length$R_0$ and the core size $R_1$ of TW Hya are smaller only by factors of $\sim$2,reflecting the disk's half size. On the opposite end, the Jeans frequency$\Omega_J$ and the angular velocity $\Omega_0$ of the smaller core of TW Hyaare larger only by factors of $\sim$2. The only striking difference is that thecentral density ($\rho_0$) of TW Hya is 5.7 times larger than that of HL Tau,which is understood because the core of TW Hya is only half the size ($R_1$) ofHL Tau and about twice as heavy ($\Omega_J$). In the end, we compare theprotostellar disks that we have modeled so far.

Theoretical model of the outer disk of TW Hya presently forming in-situ planets and comparison with models of AS 209 and HL Tau