Comparison between interferometric observables from PIONIER (black dots with error bars) and from the β-best-fit model (red squares) presented in Table 2: squared visibilities V² as a function of both spatial frequencies and baseline position angles (PA), and closure phases as a function of spatial frequencies defined at the longest baseline of the corresponding triangle. The error-normalized residuals of these comparisons are also shown (black dots); horizontal lines indicate the 0 (dashed line) and ±3σ (dotted line) reference values. The vertical dashed lines in the plots with PA abscissas indicate the PAs of the sky-projected rotation axis for the visible (PA_rot) and hidden (PA_rot − 180°) stellar poles. The two images at the bottom right show one specific intensity map, computed at the 1.62 μm spectral channel of the PIONIER data, and the T_eff map corresponding to this β-best-fit model. These images are not rotated by PA_rot, i.e., they do not represent the star in sky coordinates.