Posterior distributions of the magnetic field strength (B) considering a Gaussian prior of the internal density ( ρ_i) centred in a value equal to ρ_p = 5 × 10⁻¹¹ kg m⁻³ (pink), a Gaussian prior centred in a value equal to ρ_p = 2 × 10⁻¹⁰ kg m⁻³ (blue), and a uniform prior (black dashed line). Uncertainties in Gaussian priors are considered to be of 50%. The totally filled tube and the plausible ranges for the parameters of Fig. 1 are assumed.