Page:Illustrated Astronomy.pdf/21

Up here it would be valid to ask: Why all stars are different? Every single one of them owes all their features properties, such as color, brightness, and size to its mass and to their age. Although indeed, the chemical composition does matter, it is a secondary factor. For instance, the Sun has a mass of 1,988,000,000,000,000,000,000,000,000,000 kg (1,988x1030 kg), the so-called solar mass (M ), and we designate a number to the stars in comparison with that value. Then, Proxima has a mass of 0.123 solar masses.

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