2004/05/05 by S. J. O’Toole, S. J. O'Toole, U. Heber +2
Physics and Astronomy · #Asteroseismology #Astronomy #Astrophysics #Context (archaeology) #Gamma-ray bursts and supernovae #History #Orbital period #Physics #Pulsars and Gravitational Waves Research #Radial velocity #Stars #Stellar, planetary, and galactic studies #White dwarf #astro-ph
paper · pdf · doi:10.1051/0004-6361:20040264
published as Astron.Astrophys. 422 (2004) 1053-1058 · 7 pages, 5 figures, to appear in A&A
arxiv created 2004/05/05 · openalex publication_date 2004/07/16 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present the discovery of a binary companion to the pulsating sdB Feige 48. Using HST/STIS and archival FUSE spectra, we measure a period of d and a velocity semi-amplitude of km s-1. This implies that the companion star must either be of very low mass, or the orbit is at low inclination. Combining 2MASS fluxes, the lack of a reflection effect, results from asteroseismology and a measurement of the rotation velocity of Feige 48, we show that the orbital inclination must be ≤11.4° and that the unseen companion is a white dwarf with mass ≥0.46 . The implications of this discovery, and of binarity amongst sdB pulsators, is then discussed in the context of recent theoretical work on sdB formation. In particular we suggest that radial velocity studies focus on sdB pulsators with no known companion, and that asteroseismological studies of sdBs investigate a larger mass range than previously considered in order to test formation models.