Bibcode
Collados, M.; Martinez Pillet, V.; Ruiz Cobo, B.; del Toro Iniesta, J. C.; Vazquez, M.
Referencia bibliográfica
Astronomy and Astrophysics (ISSN 0004-6361), vol. 291, no. 2, p. 622-634
Fecha de publicación:
11
1994
Número de citas
122
Número de citas referidas
101
Descripción
We confirm recent results about the differences in temperature and
magnetic field strength between the umbra of large and small sunspots.
Five Stokes I- and V-spectra from the darkest cores of three different
umbrae have been analyzed with the inversion code of the radiative
transfer equation by Ruiz Cobo & del Toro Iniesta (1992). The run
with depth of temperature, magnetic field (strength and inclination) and
velocity along the line of sight are obtained. The larger sunspots turn
out to be cooler and possesing a larger magnetic field strength,
practically throughout the whole atmosphere. Neither significant
gradients of the line-of-sight velocity, nor of the magnetic field
inclination, are detected in any of the spots analyzed. Two model
atmospheres are given corresponding to hot (small) and cool (large)
sunspots. The models are, to a large extent, free from effects of
penumbral/photospheric stray-light because it is nearly absent in the
large spots and because in the small one, where it is important for the
Stokes I-profile, only Stokes V is considered to obtain the model
atmosphere. These are the first umbral models in the literature for
which a simultaneous determination of the magnetic field and
thermodynamic stratifications is presented. The implications of these
stratifications for the energy transport in sunspot umbrae are
discussed.