2018/11/06 by G. Alecian, M. J. Stift · 27 citations
Physics and Astronomy · #Abundance of the chemical elements #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Atmosphere (unit) #Diffusion #Low Mass #Metallicity #Physics #Star (game theory) #Star formation #Stars #Stellar atmosphere #Stellar mass #Stellar, planetary, and galactic studies #Stratification (seeds) #Thermodynamics #astro-ph.SR
paper · pdf · doi:10.1093/mnras/sty3003
published in Monthly Notices of the Royal Astronomical Society 482(4), 4519-4527 (Oxford University Press) · 10 pages, 9 figures, MNRAS in press, accepted 2018 November 1
arxiv created 2018/11/06 · openalex publication_date 2018/11/07 · arxiv updated 2018/11/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Calculating abundance stratifications in ApBp/HgMn star atmospheres, we are considering mass-loss in addition to atomic diffusion in our numerical code in order to achieve more realistic models. These numerical simulations with mass-loss solve the time-dependent continuity equation for plane-parallel atmospheres; the procedure is iterated until stationary concentrations of the diffusing elements are obtained throughout a large part of the stellar atmosphere. We find that Mg stratifications in HgMn star atmospheres are particularly sensitive to the presence of a mass-loss. For main-sequence stars with |T_\rm eff≈ 12 000| K, the observed systematic mild underabundances of this element can be explained only if a mass-loss rate of around |4.2 × 10-14| solar mass per year is assumed in our models. Numerical simulations also reveal that the abundance stratification of P observed in the HgMn star HD 53929 may be understood if a weak horizontal magnetic field of about 75 G is present in this star. However, for a better comparison of our results with observations, it will be necessary to carry out 3D modelling, especially when magnetic fields and stellar winds – which render the atmosphere anisotropic – are considered together.