2007/02/19 by S. Lefebvre, A. G. Kosovichev, J. P. Rozelot · 2 citations
Physics and Astronomy · #Ionosphere and magnetosphere dynamics #Solar and Space Plasma Dynamics #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/515394
9 pages, 2 figures, ApJ Lett in press
arxiv created 2007/02/19 · openalex publication_date 2007/03/05 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
Recent models of variations of the Sun's structure with the 11 year activity cycle by Sofia et al. predict strong nonhomologous changes of the radius of subsurface layers, due to subsurface magnetic fields and field-modulated turbulence. According to their best model, the changes of the surface radius may be 1000 times larger than those at the depth of 5 Mm. We use f -mode oscillation frequency data from the SOHO MDI and measurements of the solar surface radius variations from SOHO and ground-based observatories during solar cycle 23 (1996-2005) to put constraints on the radius changes. The results show that the above model overestimates the change of the radius at the surface relative to the change at 5 Mm.