Histogram of frequency splittings listed in Table A.3, that are determined by taking the frequency difference between subsequent entries in the sorted frequency list. The vertical indicators at 0.123 μHz, 0.205 μHz, and 0.243 μHz, reflect expected ℓ = 1, 2, 8 splittings for a rotation period of 47 days. The splittings at 0.13 μHz are identified as ℓ = 1, and the peak at 0.23 μHz as ℓ ≥ 2 modes.