外层大气温度很高。
当恒星逐渐缺少能源，它的核心部分变得越来越小，温度逐渐升高，同时使外层物质挥发。
As the star begins to run out of fuel, its core becomes smaller and hotter, boiling off its outer layers.
太阳的外层大气称为日冕，那里的温度比光球层(即我们所看到的太阳表面)的温度要高好几百度。
The Sun's outer atmosphere is called the corona and it is several hundreds of times hotter than the photosphere, or the visible surface of the star.
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