Mass loss in A and F stars - The Lambda Bootis stars

Abstract

view Abstract Citations (124) References (31) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Mass Loss in A and F Stars: The lambda Bootis Stars Michaud, G. ; Charland, Y. Abstract Chemical separation in the presence of mass loss rates ranging from 10 to the -15th to 10 to the -12th solar mass/yr is studied. Present knowledge on the abundances of metal-deficient A stars is reviewed, calculations of diffusion in the presence of mass loss are described, and the results of the calculations are presented. It is shown how the time-dependent evolution of the abundances depends on mass loss, radiative acceleration, helium content, effective temperature, and gravity. It is found that, while chemical separation leads to overabundances of most heavy elements for the smaller mass loss rates studied, it leads to underabundances by a factor of about three for most of the main sequence lifetimes of A and F stars if the mass loss rate is 10 to the -13th solar mass/yr. It is also shown that, especially in the presence of mass loss, only small overabundances of metals are to be expected in the early F stars at the same time as the observed large underabundances of Li, Be, and possibly some heavy elements. Publication: The Astrophysical Journal Pub Date: December 1986 DOI: 10.1086/164774 Bibcode: 1986ApJ...311..326M Keywords: A Stars; F Stars; Main Sequence Stars; Stellar Composition; Stellar Mass Ejection; Acceleration (Physics); Diffusion Theory; Helium; Metallicity; Time Dependence; Astrophysics; DIFFUSION; STARS: MASS LOSS; STARS: METALLIC-LINE full text sources ADS | data products SIMBAD (1)