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		| Paper: | 
		A Birth and Growth of a Collimated Molecular Jet from an AGB Star | 
	 
	
		| Volume: | 
		340, Future Directions in High Resolution Astronomy: The 10th Anniversary of the VLBA | 
	 
	
		| Page: | 
		399 | 
	 
	
		| Authors: | 
		Imai, H.; Diamond, P.J. | 
	 
	
	
		| Abstract: | 
		With the VLBA, we have observed water masers associated with the OH/IR star, W43A, which trace a birth and growth of a molecular jet. The water masers exhibit the collimated distribution (1700 AU: 20 AU) and fast motions (±150 km s−1). The maser distribution was well fit by a precessing jet model. The jet length has extended by 800 AU within 8 years, indicating that the extension rate is roughly equivalent to the jet speed (150 km s−1). Very likely the jet was born around the year 1960. An elongated planetary nebula will be formed by such a jet during an extremely short period (< < 1000 yrs) of the transition to form a ptoto-planetary nebula. Then fading of the water maser jet will be observed during our own life. | 
	 
	
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