Corner plot for SXP 15.6 using the model described in the text. We plot the logarithm of the polar magnetic field strength B in G, the eccentricity (e), the longitude of periastron in degrees (ω), the projected semi-major axis in light seconds (a sin i), the time of a mean longitude of 90 degrees T_π/2 and the pulsar frequency F₀ in mHz. The reference epoch for F₀ is the start of the NICER monitoring, i.e. MJD 59538.5.