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Project Progress

To produce pre-biotic materials in the cold circumstellar environment of the young Sun, high energy radiation may be required to stimulate chemical reactions of molecules. Strong X-rays from the stellar core can be a significant source of such radiation, and therefore the history of their X-ray activity can be quite important. With the XMM-Newton X-ray observatory, we clearly detected for the first time strong X-ray emission from one of the earliest stages of a star at the age of 10,000-100,000 years, the so-called Class 0 protostellar phase. In spite of the youth of the stellar system, the emission, originating in a super-hot plasma of ~40 million Kelvin, is one of the strongest from stars outside of flares; the X-ray luminosity is 10,000 times stronger than that of the Sun. Other Chandra and XMM observations made with an international collaboration have demonstrated that the X-ray activity of young stars correlate well with optical and infrared outbursts, and hence are likely associated with mass accretion activity. These results suggest that X-ray emission from very young stars can be quite energetic, driven by violent mass accretion activity.

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