The Cepheid period-luminosity zero-point from radial velocities and HIPPARCOS proper motions
Pont, Frederic; Feast, Michael; Whitelock, Patricia
South Africa, Switzerland
Abstract
A value for the zero-point (rho) of the Cepheid period-luminosity relation, <M_V>=2.81log P+rho, is deduced by comparing the value of the Oort constant, A, derived from radial velocities with that derived from Hipparcos proper motions. We find in this way that rho=-1.47+/-0.13, in excellent agreement with the value derived from Hipparcos trigonometrical parallaxes, rho=-1.43+/-0.10, by Feast & Catchpole in a recent paper.