HipparcosParallaxes and the Cepheid Distance Scale

Publisher Website
Google Scholar
Abstract
Hipparcos parallaxes have recently become available for a sample of Galactic Cepheids, and we have used these new distances to calibrate the Cepheid period-luminosity (PL) relation at six wavelengths (BVIJHK). Comparing these calibrations with previously published multiwavelength PL relations we find agreement to within 0.07 ± 0.14 mag, or 4% ± 7% in distance. Unfortunately, the current parallax errors for the fundamental pulsators (ranging in signal-to-noise ratio = π/σπ from 0.3 to 5.3, at best) preclude an unambiguous interpretation of the observed differences, which may arise from a combination of true distance modulus, reddening, and/or metallicity effects. We explore these effects and discuss their implications for the distance to the Large Magellanic Cloud (LMC) and the Cepheid-based extragalactic distance scale. These results suggest a range of LMC moduli between 18.44 ± 0.35 and 18.57 ± 0.11 mag; however, other effects on the Cepheid PL relation (e.g., extinction, metallicity, and statistical errors) are still as significant as any such reassessment of its zero point.
All Related Versions

This publication has 14 references indexed in Scilit: