2007/03/31 by Robert Szabo, J. Robert Buchler, Justin Bartee · 2 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Solar and Space Plasma Dynamics #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/520917
11 pages, 8 figures, accepted for publication in ApJ, minor revisions in the text and figures, (black and white version available from 2nd author's website)
arxiv created 2007/06/06 · openalex publication_date 2007/10/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
We compute the phase lags between the radial velocity curves and the light curves ΔΦ 1 = ϕ - ϕ for classical Cepheid model sequences both in the linear and the nonlinear regimes. The nonlinear phase lags generally fall below the linear ones except for high-period models, in which they lie above, and of course for low pulsation amplitudes, in which the two merge. The calculated phase lags show good agreement with the available observational data of normal amplitude Galactic Cepheids. The metallicity has but a moderate effect on the phase lag, while the mass-luminosity relation and the parameters of the turbulent convective model (time-dependent mixing length) mainly influence the modal selection and the period, which is then reflected in the period-ΔΦ 1 diagram. We discuss the potential application of this observable as a discriminant for pulsation modes and as a test for ultralow-amplitude (ULA) pulsation.