= Oblate tensor-virial shape factor
{title2=$Q(q)=W_{xx}/W_{zz}$}
For a finite stationary axisymmetric self-gravitating system with similar oblate density surfaces, let $q=b/a$, $s=\sqrt{1-q^2}$, $A_1=q\arccos(q)/s^3-q^2/s^2$, and $A_3=2/s^2-2q\arccos(q)/s^3$. Its <stellar potential-energy tensor> has $Q=A_1/(q^2A_3)$; the common radial integral cancels. The spherical limit has $A_1=A_3=2/3$ and $Q=1$. With mass-weighted in-plane <velocity dispersion> $\sigma_x$ and constant azimuthal streaming $v$, the <tensor virial theorem> gives $v^2/\sigma_x^2=2[(1-\beta)Q-1]$, where $\sigma_z^2=(1-\beta)\sigma_x^2$. Neither $Q=1/q$ nor the omission of the Cartesian streaming factor is exact.
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