年轻的恒星，名叫DG Tau，位于Taurus的恒星诞生区域，大约离地球450光年之远。图中间明亮的x射线源就是DG Tau，发射物从左上方到右下方，延伸至距离恒星700亿英里，大约是日地距离的700倍。
年轻恒星的高能x射线同样被探测到，部分通过从圆盘到恒星的物质流吸收。原本本身过于寒冷而不能倍钱德拉探测到。需要注意的是恒星下方模糊的垂直特征并不能为额外的喷射提供任何证据，但不失为一个排列4张图片的一个机会。
Guedel和colleagues一同认为强大的x射线发射物在绝大多数年轻恒星演化的过程中进一步的发展。这是很有可能的，例如，在太阳系的早期就已经存在。DG Tau已拥有与太阳一样的质量，但比起45亿岁的太阳就年轻了许多，因为只有大约100万年。自从被行星诞生地圆盘包围后，，这张新的钱德拉图像表明早期的地球及其环境已经被来自发射物的x射线冲刷了。尽管还不清楚x射线对形成中的行星的影响是否有意义，但很有可能利大于弊。通过离子化圆盘的x射线可以产生扰动，其可以对轨道上的行星产生实质上的作用，很可能帮助防止与恒星间的冲突。此外，圆盘的x射线同样对于圆盘中复杂分子的形成非常重要，为日后行星的形成做准备。
The young star, named DG Tau, is located in the Taurus star-forming region, about 450 light years from Earth. The bright source of X-rays in the middle of the image is DG Tau and the jet runs from the top left to the bottom right, extending to about 70 billion miles away from the star, or about 700 times the Earth-Sun separation.
Highly energetic X-rays are also detected from the young star, partially absorbed by streams of material flowing from the disk onto the star. The disk itself is much too cool to be detected by Chandra. Note that the faint vertical feature below the star does not show evidence for an additional jet, but is a chance alignment of four photons.
Guedel and colleagues argue that powerful X-ray jets might develop at some stage during the evolution of most young stars. They could, for example, have existed during the early stages of the solar system. DG Tau has about the same mass as the Sun, but is much younger with an age of about one million years, rather than about 4.5 billion years. Since it is surrounded by a disk where planets may be forming, this new Chandra image suggests that the early Earth and its environment may have been bathed in X-rays from a jet like DG Tau's. Although it is unknown if such X-rays would have had a significant impact on the forming Earth, it is possible that they did more good than harm. By ionizing the disk the X-rays may have generated turbulence, which could have had a substantial effect on the orbit of the young Earth, possibly helping to prevent it from making a disastrous plunge into the Sun. Furthermore, X-ray irradiation of disks may also be important in the production of complex molecules in the disk that will later end up on the forming planets.
自翻
url:http://chandra.harvard.edu/photo/2008/dgtau/
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