UV-plane coverage of our PIONIER observations for the stars HD 190658, HD 352, V1261 Ori, and ER Del.

Same as Fig. 9 for the stars FG Ser (on 3 July and 13 August 2012) and AG Peg.

PIONIER closure phases for HD 352 (in degrees) as a function of the spatial frequency in 1/rad (×10⁷). The data points are shown in red with error bars, while the model of an elongated disc with an additional punctual source that provides the best fit is indicated with blue solid dots. Given the error bars, the significance of these data, compared to zero closure phases, is very low, as all but three points do not deviate from zero more than the error bar.

Reduced χ² maps for HD 190658: shown is the reduced χ² (logarithmic scale) as a function of the angular diameter (x-axis) and the relative flux level of the background (y-axis) based on our PIONIER data. These maps were computed using LITpro assuming a uniform disc plus background model. It is clear that the minimal reduced χ² corresponds to the model without any added background.

Same as Fig. 12 for HD 352.

Same as Fig. 12 for V1261 Ori.

Same as Fig. 12 for ER Del.

Same as Fig. 12 for FG Ser as observed on 3 July 2012.

Same as Fig. 12 for FG Ser as observed on 13 August 2012.

Same as Fig. 12 for AG Peg.