CAOSP abstracts, Volume: 33, No.: 3, year: 2003
- Author(s): Koza, J.; Kučera, A.
- Journal: Contributions of the Astronomical Observatory Skalnaté Pleso, vol. 33, no. 3, p. 224-232.
- Date: 10/2003
- Title: The range of reliability of the line-of-sight velocity in a semiempirical model of a granule
- Keyword(s): line: formation, radiation transfer, Sun: photosphere, granulation, stars: atmospheres
- Pages: 224 -- 232
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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