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557 GHz Observations of Water Vapor Outflows from VY CMa and W Hydrae

Martin Harwit·Edwin A. Bergin
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Abstract

We report the first detection of thermal water vapor emission in the 557 GHz, $1_{10} - 1_{01}$ ground state transition of ortho-H$_2$O toward VY Canis Majoris. In observations obtained with the Submillimeter Wave Astronomy Satellite (SWAS), we measured a flux of $\sim 450 $Jy, in a spectrally resolved line centered on a velocity $v_{LSR} = 25 $km s$^{-1}$ with a full width half maximum of $\sim 35$ km s$^{-1}$, somewhat dependent on the assumed line shape. We analyze the line shape in the context of three different radial outflow models for which we provide analytical expressions. We also detected a weaker 557 GHz emission line from W Hydrae. We find that these and other H$_2$O emission line strengths scale as suggested by Zubko and Elitzur (2000).

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Martin Harwit, Edwin A. Bergin. 2001-12-26. 557 GHz Observations of Water Vapor Outflows from VY CMa and W Hydrae. https://doi.org/10.1086/339365

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