On the Use of Empirical Bolometric Corrections for Stars

When making use of tabulations of empirical bolometric corrections for stars (BCV), a commonly overlooked fact is that while the zero point is arbitrary, the bolometric magnitude of the Sun (MbolSun) that is used in combination with such tables cannot be chosen arbitrarily. It must be consistent with the zero point of BCV so that the apparent brightness of the Sun is reproduced. The latter is a measured quantity, for which we adopt the value VSun = -26. 76 +/- 0. 03. Inconsistent values of MbolSun are listed in many of the most popular sources of BCV. We quantify errors that are introduced by not paying attention to this detail. We also take the opportunity to reprint the BCV coefficients of the often used polynomial fits by Flower (1996), which were misprinted in the original publication.