Theoretical Limb Darkening for Classical Cepheids: II. Corrections for the Geometric Baade-Wesselink Method
arXiv:astro-ph/0304084 · doi:10.1086/374736
Abstract
The geometric Baade-Wesselink method is one of the most promising techniques for obtaining a better calibration of the Cepheid period-luminosity relation by means of interferometric measurements of accurate diameters. In this paper we present new wavelength- and phase-dependent limb darkening corrections based on our time-dependent hydrodynamic models of the classical Cepheid zeta Gem. We show that a model simulation of a Cepheid atmosphere, taking into account the hydrodynamic effects associated with the pulsation, shows strong departures from the limb darkening otherwise predicted by a static model. For most of its pulsational cycle the hydrodynamic model predicts a larger limb darkening then the equivalent static model. The hydrodynamics affects the limb darkening mainly at UV and optical wavelengths. Most of these effects evolve slowly as the star pulsates, but there are phases, associated with shocks propagating into the photosphere, in which significant changes in the limb darkening take place on time-scales of the order of less than a day. We assess the implication of our model LD corrections fitting the geometric Baade-Wesselink distance of zeta Gem for the available near-IR PTI data. We discuss the effects of our model limb darkening on the best fit result, and analyze the requirements needed to test the time-dependence of the limb darkening with future interferometric measurements.
22 pages, 5 figures, to be published on the Astrophysical Journal, June 1 2003 issue
References in corpus (3)
Cited by in corpus (22)
- A new calibration of Galactic Cepheid Period-Luminosity relations from B to K bands, and a comparison to LMC PL relations
- Cepheid distances from infrared long-baseline interferometry - I. VINCI/VLTI observations of seven Galactic Cepheids
- High resolution spectroscopy for Cepheids distance determination. I. Line asymmetry
- Physical parameters and the projection factor of the classical Cepheid in the binary system OGLE-LMC-CEP-0227
- High resolution spectroscopy for Cepheids distance determination. II. A period- projection factor relation
- High resolution spectroscopy for Cepheids distance determination. III. A relation between gamma-velocities and gamma-asymmetries
- Cepheid distances from the SpectroPhoto-Interferometry of Pulsating Stars (SPIPS) - Application to the prototypes delta Cep and eta Aql
- Galactic Cepheids with Spitzer: I. Leavitt Law and Colors
- Extended envelopes around Galactic Cepheids III. Y Oph and alpha Per from near-infrared interferometry with CHARA/FLUOR
- The angular size of the Cepheid L Car: a comparison of the interferometric and surface brightness techniques
- Cepheid distances from infrared long-baseline interferometry - II. Calibration of the Period-Radius and Period-Luminosity relations
- New Baade-Wesselink distances and radii for four metal-rich Galactic Cepheids
- HARPS-N high spectral resolution observations of Cepheids I. The Baade-Wesselink projection factor of δ Cep revisited
- Calibrating the projection factor for Galactic Cepheids
- Cepheid limb darkening, angular diameter corrections, and projection factor from static spherical model stellar atmospheres
- Mean angular diameters, distances and pulsation modes of the classical Cepheids FF Aql and T Vul - CHARA/FLUOR near-infrared interferometric observations
- VEGA/CHARA interferometric observations of Cepheids. I. A resolved structure around the prototype classical Cepheid delta Cep in the visible spectral range
- Observations of the pulsation of the Cepheid l Car with the Sydney University Stellar Interferometer
- An Error Analysis of the Geometric Baade-Wesselink Method
- Young and Intermediate-age Distance Indicators
- Calibrating the Galactic Cepheid Period-Luminosity relation from the maximum-likelihood technique
- A new method of measuring center-of-mass velocities of radially pulsating stars from high-resolution spectroscopy