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Observed Solar Spectral Line Asymmetries and Wavelength Shifts Due to Convection

Published online by Cambridge University Press:  12 April 2016

Dainis Dravins*
Affiliation:
Lund Observatory, S-222 24 Lund, Sweden

Abstract

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Convective motions are manifest in the solar spectrum as slight spectral line asymmetries and wavelength shifts. These have been studied for 311 Fe I lines. Most lines are blueshifted because the larger contribution of blueshifted photons from bright and rising granules statistically dominates over the contribution from dark and sinking intergranular lanes. Fainter lines (formed deeper) show larger blueshifts than strong lines; high-excitation lines usually are more blueshifted (preferentially formed in the hotter granules) and short-wavelength lines are more blueshifted because of increased granulation contrast there. Detailed studies of line bisector behavior as function of line parameters permit the construction of model atmospheres incorporating convective hydrodynamics. The method does not require spatially resolved observations and can be extended to studies of stellar convection.

Type
1. The Pyhsical Origin of Turbulence
Copyright
Copyright © Springer-Verlag 1980