2004/01/19 by Sheperd S. Doeleman, Colin J. Lonsdale, Paul T. Kondratko +1 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Conical surface #Maser #Offset (computer science) #Outflow #Protostar #Stellar, planetary, and galactic studies #Very-long-baseline interferometry #astro-ph
paper · pdf · doi:10.1086/383220
published as Astrophys.J. 607 (2004) 361-368 · 20 pages, 4 figures
arxiv created 2004/01/19 · openalex publication_date 2004/05/17 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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.