Massive stars as cosmic engines

大质量恒星由最初大于8个太阳质量的所有恒星组成。大约100毫升，它们在连续的、越来越热的中央壳层中燃烧元素，一直燃烧到铁，然后成为核心坍塌的超新星，留下中子星或黑洞残留物，这取决于初始质量。在100mSun以上，它们只燃烧到核心中的氧气，然后成为完全分裂的成对不稳定超新星。由于一颗正常恒星的辐射输出大致为其质量的立方，因此一颗100mSun恒星的辐射输出相当于100万个太阳的总辐射输出。在大约20mSun上方，大质量恒星通过它们的强风进一步区分自己，强风的范围高达太阳的10亿倍。因此，尽管大质量恒星很罕见且寿命很短，但它们会向星际介质发射大量的紫外线辐射和丰富的物质，准备建造更多像地球一样的恒星和行星。这一点在早期宇宙中尤其重要，当时形成的第一批恒星可能都非常大。显然，大质量恒星主导着宇宙的生态，但它们的许多基本参数仍然难以捉摸。

Massive stars comprise all stars initially above 8 solar masses (Msun). Up to about 100 Msun they burn elements in successive, ever-hotter central shells right through to iron, before becoming core-collapse supernovae, leaving a neutron star or black hole remnant depending on the initial mass. Above about 100 Msun they burn only to oxygen in their cores before becoming pair-instability supernovae with complete disruption. Since the radiative output of a normal star goes roughly as the cube of its mass, a single 100 Msun star matches the total radiation output from a million Suns. Above some 20 Msun, massive stars further distinguish themselves by their strong winds, ranging up to a billion times that of the Sun. Thus, although rare and short-lived, massive stars deliver huge quantities of mostly lethal UV radiation and enriched material to the interstellar medium, ready to build more stars and planets like Earth. This was especially important in the early Universe, when the first stars formed were probably all very massive. Clearly, massive stars dominate the ecology of the Cosmos, yet many of their basic parameters remain elusive.