1999/08/25 by Y. Lebreton, Lebreton, Y., M. N. Perrin +8
Physics and Astronomy · #Astro and Planetary Science #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #FOS: Physical sciences #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9908277
13 pages, 6 figures in press at A&A
arxiv created 1999/08/25 · openalex publication_date 1999/08/25 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
From an initial sample of a few hundred stars selected for an Hipparcos program, a subsample of 33 objects with direct determination of their effective temperature, bolometric magnitude and [Fe/H] has been derived. An accurate observational (logTeff, Mbol) HR diagram has been obtained, and compared to theoretical isochrones. Attention has been concentrated on the cool part of the HR diagram, for which evolutionary effects are negligible. Whereas solar metallicity stars show a reasonable agreement with theoretical expectation, a clear discrepancy occurs for stars more metal-poor than [Fe/H] = -0.5. This discrepancy is reduced to practically zero, if corrections to LTE abundances are taken into account for Fe, and if sedimentation effects are included in stellar evolution computations.