Position of 18 Peg in a (T_eff,log (g)) diagram based on spectroscopy (red error bars; Nieva & Przybilla 2012), photometry (blue error bars; this work), and preliminary asteroseismology (green square; this work; T_eff taken from spectroscopy). Overlaid are evolutionary tracks for non-rotating stars of solar metallicity and different initial masses by Brott et al. (2011, dashed lines) and Ekström et al. (2012, solid lines). The numbers next to the black filled circles give the evolutionary age in Myr. The gray-shaded areas highlight the transition region between MS and post MS for the two different sets of models. The impact of stellar rotation is demonstrated via the dotted line, which is an Ekström et al. (2012) track for a rotating (Ω / Ω_crit = 0.4) star with an initial mass of 4 M_⊙.