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		| Paper: | 
		Mass Loss and Magnetospheres: X-rays from Hot Stars and Young Stellar Objects | 
	 
	
		| Volume: | 
		262, The High Energy Universe at Sharp Focus: Chandra Science | 
	 
	
		| Page: | 
		31 | 
	 
	
		| Authors: | 
		Gagné, M.; Cohen, D.; Owocki, S.; Ud-Doula, A. | 
	 
	
	
		| Abstract: | 
		The discovery of strong X-ray emission from hot stars was one one of the early surprises of the Einstein mission. Although wind shocks may produce most of the soft X-rays on some O stars, some young OB stars show variable hard X-ray emission that cannot be explained by standard instability-driven wind shocks. I present recent efforts to synthesize X-ray spectra of magnetically confined wind shocks. On the other end of the H-R diagram, X-ray flares on low-mass young stellar objects exhibit plasma temperatures >50 MK, variable column densities, and very high emission measures, suggesting enormous magnetic loops. In high-mass and low-mass young stars, rotation, magnetospheres and disks may play a key role in the X-ray emission process. | 
	 
	
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