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Solar Line Asymmetries:
Modelling the Effect of Granulation on the Solar Spectrum
Abstract
A parametric model of granulation employing a small number of parameters was developed.
Synthetic spectra calculated using this model closely match observed spectra and, in particular,
reproduce the asymmetries observed in spectral lines. Both the microturbulent motions and the
large-scale flow velocity decrease exponentially with a scale height of 368 km as the height within
the photosphere increases. The model agrees with observations of the solar granulation (from
which it was derived).
The horizontal motions associated with granulation were found and used to calculate spectra
emergent away from disk centre. These calculated spectra were compared to observed spectra,
with the agreement supporting the accuracy of the granular model.
Also in the course of this work, the Brueckner-O'Mara damping theory was found to predict
damping constants accurately. The photospheric abundances of a number of elements were
determined. The abundance obtained for iron agrees with the meteoric iron abundance.
Astrophysical f-values for some lines were also determined.
Obtaining a copy
Download entire thesis:
[pdf, zipped, 2.2Mb]
or see next section for individual chapters. Or, email me. Also available as postscript.
Outline
Front matter
Introduction to the asymmetry present in solar lines
A textbook on the formation of the solar spectrum
Granulation
Modelling granulation and calculating asymmetric spectral lines. Results.
Data
Bibliography