CBSE Class 12-science Answered

Hi dear,

The effect you're seeing is almost certainly due to refraction in the atmosphere. The probable reason that only certain stars seem to change color is that it requires a certain light level before the human eye can distinguish colors (lower than that, you only see a grayscale). So only the brightest stars (Arcturus is the fourth brightest, fifth including the Sun) will exhibit this type of sparkling. Dimmer stars only twinkle (move around and change brightness).

Hope this helps.

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