Isotropic Jeans-Abel mass inversion

For equal-luminosity stars in a spherical isotropic equilibrium, both $I(R)/L$ and $I(R){\sigma }_{\mathrm{los}}^2(R)/L$ are Abel projections of $\nu$ and $\nu {\sigma }_r^2$. Separate inversion recovers the number density and radial stress; $M(r)=-r^2[d(\nu {\sigma }_r^2)/dr]/(G\nu )$. The stellar luminosity cancels in this mass ratio. Unknown anisotropy, noisy derivatives and limited outer coverage require additional modelling.