Fourier analysis of Fe I lines in the spectra of the Sun, α Centauri A, Procyon, Arcturus, and Canopus
Abstract
We used spectral observations of Fe I line profiles with a 200 000 resolution to determine micro and macroturbulent velocities in the atmospheres of the Sun as a star, α Cen A, Procyon (α CMi), Arcturus (α Boo), and Canopus (α Car). Isotropic microturturbulent velocities (Vmi) and radial-tangential macroturbulent velocities (Vma,RT) were found to be a quite suitable approximation to the velocity field in the atmospheres of all stars studied except Canopus. The average velocities Vmi and Vma,RT are 0.8 +/- 0.1 and 2.6 +/- 0.3 km/s for the Sun as a star, 0.8 +/- 0.2 and 2.9 +/- 0.4 km/s for α Cen A, 0.8 +/- 0.3 and 5.9 +/- 0.2 km/s for Procyon, 1.0 +/- 0.2 and 4.6 +/- 0.3 km/s for Arcturus. The velocity field in the atmosphere of Canopus can be described by an anisotropic radial-tangential distribution of microturbulence with Vmi,RT = 2.1 km/s and anisotropic distribution of macroturbulence with Vma,rad = 17 +/- 2 km/s and Vma,tan = 1.3 +/- 1.0 km/s. From Fourier analysis of broadening and shapes of three spectral lines of Fe I, we have derived the rotation velocity Ve sini = 3.5 +/- 0.2 km/s for Canopus.