Bibcode
Sobotka, M.; Bonet, J. A.; Vazquez, M.
Referencia bibliográfica
Astronomy and Astrophysics (ISSN 0004-6361), vol. 257, no. 2, p. 757-762.
Fecha de publicación:
4
1992
Número de citas
14
Número de citas referidas
14
Descripción
A photometric study of umbral bright features (umbral dots, clusters of
umbral dots, bright grains of light bridges) in sunspots is presented.
It is based on white-light images taken with a CCD video camera driven
by an automatic image selection system. A direct linear relation between
the observed brightness of the features and that of the surrounding
background areas has been found. To eliminate the influence of the
seeing on this result, the radiative fluxes, which are much less
sensitive to the image degradation, have been examined and an analogous
relation has been found. Finally, a possible physical explanation is
suggested.