Aperture synthesis observations of Orion-KL in CS lines and 3mm continuum

Abstract

We have made aperture synthesis maps toward the Orion-KL nebula in CS(1-0), CS(2-1) and 3mm continuum with the Nobeyama Millimeter Array (NMA). The CS(1-0) maps were obtained across the central 2′ region of the Orion-KL nebula. Our maps show the rotating disk around the KL nebula with the diameter of 0.3 pc and the mass of 25 M⊙. The disk clearly shows the Keplerian rotation, which indicates that the mass of the KL nebula is 100 — 150 M⊙. The shell structure around the molecular outflow is also found in CS(1-0) map. This structure also appears in CS(2-1) map.From 3mm continuum map, we have found at least six continuum sources. One of them is f-f emission from the ultra-compact HII region around BN. Other sources are the dust clumps whose masses are estimated to be 1 — 4 M⊙. The distribution of the dust clumps shows clear anti-correlation with the 20 μm emissions. This indicates that the 20 μm emissions are obscured by these dust clumps.