Highlights - Volume 469-2 (July II 2007)

“Three-dimensional hydrodynamical simulations of surface convection in red giant stars. Impact on spectral line formation and abundance analysis”, by R. Collet et al. A&A 469, p. 687

This article describes 3-D simulations of line formation in the atmospheres of metal poor red giants. The authors find that this accounts for the granulation of actual giant atmospheres resulting in significantly lower CNO abundances compared with equivalent 1-D analyses, but they caution that neglected departures from local thermal equilibrium might require them to alter their conclusion.

“Stokes diagnostics of simulated solar magneto-convection”, by S. Shelyag et al. A&A 469, p. 731

The authors of this paper performed radiative MHD simulations of solar photospheric granulation with a magnetic field. They compared synthetic Stokes profiles of neutral iron lines with observational results. The results of the simulations confirm that the line weakening in a strong magnetic field is caused by the increased temperature in the magnetic flux concentrations.