Graphical summary of the results of the IACOB-GBAT analysis for the O7 V((f))z star HD 47839, representative of the He-poor abundance group. Although not detected in the optical spectrum or through radial-velocity (RV) measurements (the peak-to-peak RV dispersion measured from 109 spectra in the IACOB spectroscopic database, spanning nearly nine years, is only 3.4 km s⁻¹, Simón-Díaz et al. 2024), HD 47839 is known to be a long-period binary system (∼25 yr, Gies et al. 1997), including a fast-rotating B-type companion (see also Burssens et al. 2020).