CAOSP abstracts, Volume: 33, No.: 3, year: 2003

Abstract: Stokes I response functions to the line-of-sight velocity vLOS of two medium-strong Fe I 522.5 nm and Fe I 557.6 nm lines and the weak line Fe I 557.7 nm have been calculated using a semiempirical 1D model of the granular photosphere affected by 5-min oscillations. A new method is presented allowing to estimate the range of optical depths within which the inferred values of an atmospheric parameter can be considered as reliable. The sensitivity of the individual lines to the variations of vLOS is examined and the range of reliability of vLOS is estimated applying the new method. It is shown that for the given line set the Fe I 522.5 nm line is the most sensitive one and, in turn, the Fe I 557.7 nm line has very low sensitivity to the variations of vLOS. In the case of the Fe I 522.5 nm line the impact of a vLOS perturbation on the intensity of a profile point is about 50% greater than that on the Fe I 557.6 nm line. As a consequence of evolution of the physical conditions in a granule the range of reliability of the model varies and it consists of two separate regions occupying the lower and upper photosphere.

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Last update: November 10, 2003