科学美国人60秒 SSS X射线可能照射到一些可居住外行星区域

Some Habitable Zone Exoplanets May Get X-Rayed Out X射线可能照射到一些可居住外行星区域

As astronomers 2 hunt for habitable, Earth-like worlds, one popular place to look is around M stars, a type of red dwarf 3. Couple reasons for that:

当天文学家寻找可居住的类似地球的世界时，一个看起来很受欢迎的地方是M星，这是一种红矮星。有以下几个原因：

"First of all most of the stars in our galaxy 4 are like that." Eike Guenther is an astronomer 1 at the Thüringer State Observatory 5 in Germany. "And secondly 6 the closest stars to us are like this. And thirdly, it's relatively 7 easy to find planets around them which have a low mass or small diameter."

“首先，我们星系中的大多数恒星都是这样的。”Eike Guenther是德国图林根州立天文台的天文学家。他说，“其次，对我们来说，最接近的恒星就是这样的;第三，找到它们周围的质量较小或者直径较小的行星比较容易。”

M stars are smaller and fainter than our Sun. Meaning the zone around them where liquid water could exist—the habitable zone—is really close in. And in that region around the star it’s also easier to spot small exoplanets, with current techniques.

M星是比我们的太阳更小更暗淡的行星，这意味着，它们周围的区域，可以存在液态水——也就是可居住区域——这种联系非常密切。在恒星周围的区域，使用目前的技术，也可以更容易地发现小型系外行星。

A few months back, Guenther had his telescope trained on an M star 16 light-years away, known as AD Leonis, when he spotted 8 a huge stellar flare 9. A Neptune-sized giant exoplanet lurking 10 around the star appears to have survived unscathed. But the event inspired Guenther and his team to ask how that huge flare would have affected 11 a hypothetical Earth-sized exoplanet orbiting the star. So they ran a computer simulation.

几个月前，盖因尔望远镜探测到了距今16光年远的一颗M星，当时他发现了一颗巨大的恒星耀斑，称为AD莱昂尼斯。一颗潜伏在恒星周围的海王星大小的系外行星，似乎没有受到伤害。但是这一事件激励了Guenther和他的团队，去研究这个巨大的耀斑，如何影响了一颗假想的地球大小的系外行星围绕恒星旋转。所以他们进行了计算机模拟。

The result? The shower of X-rays, thousands of times stronger than what the Sun unleashes 12 on the Earth, would have blasted away much of the imaginary exoplanet's protective ozone 13. And multiple such flare events would be disastrous 14 for life as we know it.

结果呢?X射线的阵雨比太阳在地球上释放的能量强数千倍还多，这会使大部分假想的系外行星的保护性臭氧爆炸。正如我们所知道的那样，多次这样的闪光事件，对于生命将是灾难性的。

"So this analog 15, of taking the Earth, and saying, 'Ok, we put it in the habitable zone, and that's how a habitable planet looks like’—that's presumably wrong. One now has to consider these very energetic events that change the properties of the atmospheres of the other planets."

“所以，拿地球打个比方说：'好吧，我们把它放在可居住的地区，这就是一个可居住的星球的样子' ——这大概是错误的。现在我们必须考虑这些非常有活力的事件，其他星球大气层的特性”。

He presented the observations at the recent European Week of Astronomy and Space Science conference in Liverpool.

他在最近的欧洲利物浦天文与空间科学周会议上发表了观察结果。

Guenther says, if anything, this finding makes the weird 16 planets hugging M-stars even more intriguing 17, in terms of planetary diversity. "I would say… keep looking!"

Guenther说，如果有的话，这个发现使得拥有M星的奇怪行星更具吸引力，就行星多样性而言是这样的。“我会说......继续寻找!”

NASA's Transiting 18 Exoplanet Survey Satellite, or TESS, is set to launch April 16th… if all goes well… it'll soon be looking too.

美国宇航局的太空行星外行星测量卫星(TESS)，将于4月16日发射......如果一切顺利的话...它很快就会看起来很美。