New fundamental stellar parameters of the primary (A) component of HD 104237, located in the HR diagram of Böhm et al. (2004). The location of the secondary component HD 104237 b (B) is also indicated. The luminosity and effective temperature pairs reported in van den Ancker et al. (1998) (VA) and Grady et al. (2004) (GR) are shown in the diagram, including their estimated error bars, along with our new parameters (FB), associated with error with an 68.3% confidence interval. Evolutionary tracks (1.5, 2.0 and 2.5 M_⊙) and isochrones are by Palla & Stahler (2001). The Marconi & Palla (1998) instability strip is represented by the shaded area.