1999ApJ...525..209T

In this paper, we make a comprehensive determination of the Hubble constant H₀ by using two parameters–the B-V color and the rate of decline Δm₁₅–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 χ² 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 H₀=62 km.s^–1.Mpc^–1 and a standardized absolute magnitude of -19.46. The sensitivity of H₀ to a metallicity dependence of the Cepheid-determined distances is investigated. The total uncertainty δH₀, dominated by uncertainties in the primary distance indicators, is estimated to be 5 km.s^–1.Mpc^–1.