Position of HD 261711 in the HR-diagram in comparison with isochrones (top panel) and evolutionary tracks (bottom panel). In both panels the ZAMS is indicated by a grey, solid line and the borders of the δ Scuti instability strip are marked with thick solid lines. The position of HD 261711 is given with a filled square. Top panel: isochrones with ages of 6, 8 and 10 Myr are indicated with a dash-dotted, solid and dashed line. Bottom panel: PMS evolutionary tracks for 1.5, 2.0 and 2.5 M_⊙ are shown with dashed lines, (post-)main sequence evolutionary tracks for the same masses with solid lines. The open symbols mark the positions of HD 34282 (down triangle) and HD 144277 (up triangle).