Observations of Changes in the Photospheric Granules

Abstract

Using a sequence of 29 good-quality photographs extending over a period of 10 min, an attempt is made to detect changes in the brightness, size, and shape of individual granules. Of the 125 granules for which there is sufficient data, 57 per cent. show no detectable change during their observed periods of persistence, an additional 14 per cent. showing only minor changes of shape. Although there is some tendency among granules showing change for size increases to predominate over decreases, brightness increases and decreases occur with equal frequency. There is no correlation between the two types of change, nor is there any tendency for brightness or size variations to occur during any particular part of the life cycle. Observations with higher resolving power are required to elucidate the changes occurring during the formation and dissolution·of individual granules.