Bolometric correction ($B{C}_X=M_{\mathrm{bol}}-M_X$)

The adjustment from an astronomical magnitude in a particular observational band to the bolometric magnitude, accounting for energy outside that band. It depends on the stellar spectrum, hence on effective temperature, composition and surface gravity. A ratio of observed single-band luminosities should not be inserted into the Stefan–Boltzmann law as a bolometric ratio without allowing for different corrections.