SIMBAD references

We report the first detection of thermal water vapour emission from a circumstellar outflow. We have observed four far-infrared rotational emission lines of water vapour and one water absorption feature toward the evolved star W Hydrae, using the Short Wavelength Spectrometer (SWS) of the Infrared Space Observatory (ISO). Three of the emission lines were observed in the instrument's Fabry-Perot mode at a resolving power λ/{DELTA}λ of approximately 30000: the 7₂₅-6₁₆line at 29.84µm, the 4₄₁-3₁₂line at 31.77µm, and the 4₃₂-3₀₃ line at 40.69µm. One additional emission line, the 4₄₁-4₁₄line at 37.98µm, and one absorption feature at 38.08µm that we attribute to a blend of the 13_13,0-13_12,1 and the 13_13,1-13_12,2 water lines were observed in grating mode at a resolving power of about 2000. The observed emission line fluxes were 3.2x10^–19, 6.3x10^–19, 2.3x10^–19 and 2.8x10^–19W.cm^–2 respectively, and the equivalent width of the absorption feature was ∼10km.s^–1. To within the possible errors in the flux calibration, the observed emission line fluxes can be accounted for simultaneously by a model similar to that of Chen & Neufeld (1995), given a mass-loss rate in the range (0.5-3)x10^–5M_☉/yr. This range lies at least a factor ∼2 above an independent estimate of the mass-loss rate that may be derived from dynamical considerations, and at least a factor ∼30 above previous estimates based upon the interpretation of CO observations.