x-ray

• Astronomers have also detected older and smaller m stars, previously thought to be quite dim, that actually outshine the sun in their x-ray emission .
  天文学家还探测到有一些较老较小的M型星，它们发射的X射线实际上比太阳更加光辉灿烂，而先前人们却认为它们是十分幽暗的。