Determination of the Hubble constant using a two-parameter luminosity correction for type Ia supernovae

In this paper, we make a comprehensive determination of the Hubble constant H-0 by using two parameters-the B-V color and the rate of decline Delta m(15)-to simultaneously standardize the luminosities of all nearby Cepheid-calibrated Type Ia supernovae (SNe Ia) and those of a larger, more distant sample of 29 SNe Ia. Each group is treated in as similar a manner as possible in order to avoid systematic effects. A simultaneous chi(2) minimization yields a standardized absolute luminosity of the Cepheid-calibrated supernovae as well as the Hubble constant obtained from the more distant sample. With an adopted LMC distance modulus of 18.50, we find H-0 = 62 km s(-1) Mpc(-1) and a standardized absolute magnitude of -19.46. The sensitivity of H-0 to a metallicity dependence of the Cepheid-determined distances is investigated. The total uncertainty delta H-0, dominated by uncertainties in the primary distance indicators, is estimated to be 5 km s(-1) Mpc(-1).