Driver orbit from the motion of the S1 spiral pattern, overlaid on observations in the SPHERE H band 𝒬_ϕ (top; UT 2023 September 20) and ALMA Band 7 continuum (bottom; UT 2017 August 9). For a central star with 2.0 ± 0.1 M_⊙, the yr⁻¹ counterclockwise motion of the S1 spiral corresponds to a driver at 118 ± 20 au, or . Subject to motion measurement uncertainties here, the derived orbit is consistent with the ≈120 au ALMA gap-opener proposed in Kraus et al. (2017) within 1σ.