denominator of the constraint ρ = 3/4πGP2r13. If an absoluteradius R is estimated from separate evidence, thedensity is alternatively constrained by ρ = 3g/4πGR, butagain a relatively large proportional error in the observationallydetermined value of the surface gravity g wouldcompromise the density estimate (Muirhead et al. 2012;Rhodes and Budding 2014).