Labels:text | screenshot | font | number OCR: COOL GIANT WHILE A MAIN-SEQUENCE star such as the Sun has a core temperature of about 15 million ℃ (27 million "F), the core temperature of a red giant eventually reaches about 100 million ℃ (180 million ºF). The surface temperature of the red giant is lower than that of the main-sequence star, however, because the giant's surface lies a greater distance from its core. When the Sun becomes a red giant in about 5 billion years' time, its diameter will increase from about 1.4 million km (870,000 miles) to at least 200 million km (125 million miles).
