2008/02/19 by Joel A. Eaton, J. A. Eaton · 1 citation
Mathematics · Physics and Astronomy · #Astro and Planetary Science #Astrophysics #Astrophysics and Star Formation Studies #Binary number #Binary star #Binary system #Common envelope #Contact binary #Distortion (music) #Envelope (radar) #Light curve #Mathematics #Optics #Physics #Radiative transfer #Spurious relationship #Stars #Statistics #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/588270
14 pp, 2 tables, 12 fig; under review by ApJ
arxiv created 2008/02/19 · openalex publication_date 2008/07/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
I discuss the effect of physical distortion on the velocities of close binary components and how we may use the resulting distortion of velocity curves to constrain some properties of binary systems, such as inclination and mass ratio. Precise new velocities for 5 Cet convincingly detect these distortions with their theoretically predicted phase dependence. We can even use such distortions of velocity curves to test Lucy's theory of convective gravity darkening. The observed distortions for TT Hya and 5 Cet require the contact components of those systems to be gravity darkened, probably somewhat more than predicted by Lucy's theory, but clearly not as much as expected for a radiative star. These results imply there is no credible evidence for eccentric orbits in binaries with contact components. I also present some speculative analyses of the observed properties of a binary encased in a nonrotating common envelope, if such an object could actually exist, and discuss how the limb darkening of some recently calculated model atmospheres for giant stars may bias my results for velocity-curve distortions, as well as other results from a wide range of analyses of binary stars.