Identification of the individual mode geometry for F1 studying line 1. The plots correspond to the normalized intensity of the studied spectral line (left), amplitude of the variation (middle), and phase (right). The observations are plotted with a green dotted line and the error bars are included in green as well. The two most suitable identifications are plotted with a dashed black line for (l, m) = (3, 1), which was obtained with a χ² of 1.88, and a solid red line for (l, m) = (2, 1), which was obtained with a χ² of 2.43.