Annu. Rev. Astron. Astrophys. 1992. 30: 359-89 Copyright © 1992 by Annual Reviews. All rights reserved

3.6 Summary of Calibrations

The adopted values of M_B⁰⁰ from the various calibration methods are listed together in Table 5. Not one of the individual values can be regarded to be free of the possibility of serious external error, but the mutual consistency of these independent estimates is encouraging. Assigning double weight to the absolute magnitudes obtained from the Virgo cluster SNe Ia and from the radioactivity method, and disregarding the thermal emission estimate on the grounds that the external error is unknown but may be large, we obtain as the best current estimate M_B⁰⁰ = - 19.6 ± 0.2.