The diversity of colours, shapes, and sizes of planetary nebulae make them fascinating objects. In this photo release Calar Alto presents a rather unique view combining both optical and near-infrared data of the Ring Nebula (M57). ...
Planetary nebulae represent the final stage in the evolution of stars whose masses are smaller than eight times that of the Sun. The approach of the final energy crisis that marks stellar old age transforms the star into a red giant whose stellar winds fill their surroundings with a thin envelope composed mainly from hydrogen gas.
Ring Nebula (M57) – click for 1600×1169 image
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