Log of observations of the HD 72106 system obtained with ESPaDOnS. Integration times refer to the complete set of four subexposures used to produce each Stokes V spectrum (Donati et al. 1997). Peak S/N values are reported for the original reduced spectra with 1.8 km s⁻¹ spectral pixels. Magnetic measurements for combined observations refer to results for the reconstructed spectra of the primary. The letter D in the LSD detection column indicates that the Stokes V LSD profile is inconsistent with the null field hypothesis at the 99.999 per cent confidence limit, indicating the presence of a magnetic field. The letter N indicates that the inconsistency was at the 99.9 per cent limit or less, and hence cannot be take as strong evidence for the detection of a magnetic field. The letters MD indicate a ‘marginal’ detection, with a value between 99.9 and 99.999 per cent, and are considered suggestive of a magnetic field, but not conclusive. (Donati, Semel & Rees 1992; Donati et al. 1997). Note that the observation from 2005 February was first published by Wade et al. (2005).