Fit of the PIONIER data by the LDD and hotspot model. Only spatial frequencies lower than 51 arcsec^-1 were considered. Insets in the left column: PA color-coded (u,v) coverage. North is up and East is left. Left column: squared visibilities with matching colors. Right column: closure phases. The best-fitted model is represented in black. The four rows correpond to the 2012 January epoch (first row), 2013 February epoch (second row), 2014 January epoch (third row), and 2014 November epoch (fourth row). For this latter epoch, a two-spots model was used and the whole spatial frequency range was considered.