2007/11/19 by Giovanni Natale, Marcella Marconi, M. Marconi +2 · 1 citation
Physics and Astronomy · #Amplitude #Angular diameter #Astro and Planetary Science #Astronomy #Astrophysics #Extinction (optical mineralogy) #Light curve #Luminosity #Optics #Parallax #Physics #RADIUS #Radial velocity #Solar and Space Plasma Dynamics #Stars #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/526518
accepted for publication on ApJ Letters
arxiv created 2007/11/19 · openalex publication_date 2008/01/30 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present a theoretical investigation of the light, radius, and radial velocity variations of the prototype δ Cephei. We find that the best-fit model accounts for luminosity and velocity amplitudes with an accuracy better than 0.8 σ, and for the radius amplitude with an accuracy of 1.7 σ. The chemical composition of this model suggests a decrease in both helium (0.26 vs. 0.28) and metal (0.01 vs. 0.02) content in the solar neighborhood. Moreover, distance determinations based on the fit of light curves agree at the 0.8 σ level with the trigonometric parallax measured by the Hubble Space Telescope ( HST ). On the other hand, distance determinations based on angular diameter variations, which are independent of interstellar extinction and of the p -factor value, indicate an increase of the order of 5% in the HST parallax.