| Issue |
EAS Publications Series
Volume 3, 2002
Star Formation and the Physics of Young Stars: Summer school on Stellar Physics X
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|---|---|---|
| Page(s) | 85 - 109 | |
| DOI | https://doi.org/10.1051/eas:2002047 | |
| Published online | 25 September 2002 | |
J. Bouvier and J.-P. Zahn (eds)
EAS Publications Series, 3 (2002) 85-109
The physics of young stellar objects: X-rays, magnetism, and high-energy phenomena
Service d'Astrophysique du CEA, Saclay, France
The association between star-forming regions and X-ray emission was discovered as soon as X-ray satellites became available, over 30 years ago. However, understanding of the nature of this association really started when X-ray images and the resulting source identification could be obtained. We now know that essentially all young stellar objects, T Tauri stars and protostars, are X-ray emitters, although the case of the youngest, Class 0 protostars, is less clear. The paper briefly reviews X-ray emission and absorption mechanisms, and emphasizes the "solar paradigm" for the interpretation of the X-ray emission, originating in the magnetic activity of young stellar objects. The possibility of star-disk magnetic interactions in protostars is also examined. In addition, feedback effects on the circumstellar disks are presented: ionization, and the associated coupling with magnetic fields; particle irradiation, and its consequences for the origin of "extinct radioactivities" in meteorites.
© EAS, EDP Sciences, 2002