When the Sun first became a main sequence star, it radiated only 70% of the current luminosity.

当太阳首次成为主序星，它的辐射只有当前光度的70％。

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A star during most of its life is a main-sequence star, which consists of a core, radiative and convective zones, a photosphere, a chromosphere and a corona.

一颗恒星其生命的绝大部分处于主序星阶段，在这一阶段它包含一个核心、辐射区和对流区、光球层、色球层和日冕。

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The star used to be like the sun, a "main sequence" star that burns hydrogen by nuclear fusion, producing helium.

这颗恒星曾和太阳一样，是颗“主序星”(“main sequence”)。它通过核聚变燃烧氢，从而产生氦。

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