Variation in continuum brightness and equivalent widths of lines in sunspot penumbrae

Abstract

Variations in the continuum brightness and in the equivalent widths of lines have been observed in the sunspot penumbral spectra. Darker regions in the continuum of the penumbrae show widening of lines, while the brighter parts show decrease in widths. A negative correlation between the continuum brightness and the equivalent widths of lines is obtained. The brightness variation in the penumbrae suggests that it is due to aggregates to individuals penumbral filaments