X-ray luminosity as a function of spin-down luminosity for the collection of thermally emitting isolated neutron stars from Potekhin et al. (2020). The luminosity limits inferred for J1317 are shown in green (for a distance of 185 pc) and black (for a distance of 1 kpc). The grey box indicates the parameter space constrained by the current data, assuming distances within 0.1–1 kpc and the spin-down limit from the timing analysis Ṗ ≤ 8 × 10⁻¹¹ s s⁻¹(3σ). The dashed black line indicates where both luminosities are equal in value.