Left: the AMBER (crosses: 2008; pentagons: 2012), PTI (circles) and IOTA (plusses) H band squared visibilities. Right: the CHARA Array CLASSIC (diamonds) and CLIMB (squares) H band visibility amplitudes. The red triangles are the 2007 AMBER data, which are treated separately. In both plots the same five geometric star+ring models are depicted. The full blue and green, dashed cyan, and dot-dashed magenta lines are models with inner diameters and widths equal to 3.0 and 4.6, 4.1 and 4.0, 1.0 and 5.5, and 5.0 and 2.5 mas, respectively. The dotted red line is the best-fit model to the 2007 AMBER data (see text). The legend denotes the value of the corresponding model, except for the red one, which formally has too few data points.