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Using VLBI to Probe the Orion-KL Outflow on AU Scales

Sheperd S. Doeleman·Colin J. Lonsdale·Paul T. Kondratko·C. Read Predmore
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Abstract

We present the first contemporaneous 43GHz and 86GHz VLBI images of the v=1 J=2-1 and J=1-0 SiO masers in the Orion-KL nebula. Both maser species exhibit the same general morphology of earlier J=1-0 maser images which appear to trace the edges of a bi-polar conical outflow. Surprisingly, the J=2-1 masers form further from the central protostar than the J=1-0 masers, a fact not readily explained by current SiO maser pumping models. The average magnitude of offsets between corresponding regions of the two masing transitions is approximately 14% of the total radial extent of the SiO maser emission. This offset indicates that each transition must trace different physical conditions.

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Sheperd S. Doeleman, Colin J. Lonsdale, Paul T. Kondratko, C. Read Predmore. 2004-01-19. Using VLBI to Probe the Orion-KL Outflow on AU Scales. https://doi.org/10.1086/383220

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