K_p–v_sys map showcasing the injection-recovery test on NIRPS data. Left panel: the injected iron atmospheric model includes contributions from the H⁻ as a source of continuum opacity; the map shows no detection of atomic Fe in the near-infrared data of WASP-189b, consistent with non-injected results. Right panel: the injected iron atmospheric model does not include contributions from the hydride; in this case, the map shows a clear detection of neutral Fe in the near-infrared data. Black dashed lines denote the expected v_sys and K_p determined from Prinoth et al. (2023).