Comparison between our T_eff and log g values (filled circles) and those in the literature (Boesgaard et al. 2001; Bruntt et al. 2004; da Silva et al. 2011; Fuhrmann 2004, 2011; Gillon & Magain 2006; Gray et al. 2003; Kovtyukh et al. 2004; Mishenina et al. 2004, 2008; Neves et al. 2012; Ramírez et al. 2013; Reddy et al. 2003; Takeda et al. 2007; Valenti & Fischer 2005). The values obtained for HD 43587 by Bruntt et al. (2004) and Gillon & Magain (2006) using different methods are plotted separately. Filled triangles: parameters derived from excitation and ionisation balance of the iron lines, open triangles: parameters derived using different techniques. Also shown are the results of Casagrande et al. (2011) for HD 42618 based on colour indices (C11) and those for HD 43587 of Bruntt et al. (2004; B04) and Gray (1994; G04) based on line-depth ratios. The horizontal strip corresponds to the 1-σ error bar for the surface gravity determined from seismic scaling relations (see Sect. 5.1).