耀星也疯狂
Flare Star Goes Wild in Minutes
The star WX UMa went from 5,000 degrees Fahrenheit to 30,000 degrees F in less than three minutes. Chris Crockett reports
3分钟之内，一颗名为WX UMa的耀星的体温从5000华氏度猛窜了到30000华氏度。
撰文/播音 克里斯·克罗克特(Chris Crockett)
翻译 李轩
Imagine if your living room zoomed from a comfy 70 degrees to 3,000 in less time than it usually takes to boil an egg. Well, a star did the equivalent—it went from 5,000 degrees Fahrenheit to 30,000 degrees in less than three minutes. And got 15 times brighter in the process.
想像一下这是什么感觉：在不到煮熟一枚鸡蛋的时间里，你的卧室温度从70度猛增到了3000度。一颗星星就经历了这样的过程——在3分钟内，它从5000华氏度激增至30000华氏度，而亮度变为了原来的15倍。
Sixteen light-years away, the star WX Ursa Majoris is what’s called a “flare star.” It’s usually a red dwarf: cooler, fainter and smaller than the sun. But every so often, it goes wild.
16光年外的恒星WX Ursa Majoris是一颗所谓的“耀星”。耀星通常是红矮星，它比太阳更冷、更暗，也更小，不过，它的脾气可不太好。
Why certain stars flare remains a mystery. But astronomers think it starts with a disruption in the star’s magnetic field. Parts of the field twist, break and reconnect. As they do, energy gets pumped into the star’s atmosphere, and the candle becomes a searchlight. The observations are in the journal Astrophysics. [N. D. Melikian et al., Spectral observations of flare stars in the neighborhood of the sun]
这类恒星为何会“闪耀”，仍然是一个未解之迷，但天文学家认为，这是由恒星磁场破裂引发的。恒星的部分磁场在扭曲、破裂，并再次接合的过程中，能量被泵入恒星的大气层，于是“蜡烛”就变成了“探照灯”。这项观测结果发表在了《天体物理学期刊》上。
WX orbits another, bigger star. Astronomers are watching to see if that neighbor is an instigator. Should future flares sync to the stars’ orbits, we’ll gain insights into flare stars and on how binary stars affect one another. The research should shed some light.
WX围绕着另一颗更大的恒星旋转。天文学家正在观察，想确认这个邻居是否是一切的始作俑者。如果观察的结果发现，耀星的爆发周期与真与其旋转周期同步，我们将对耀星获得进一步的认识，并了解双星系统如何相互作用。新的研究一定会给我们启示。
译者注：耀星是一种变星，其亮度会在几分钟内不可预知地猛增。一般认为，耀星的闪耀类似于太阳耀斑爆发（原因是大气层中的磁场重联），其亮度的增加贯穿从X射线到无线电波的整个光谱。
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