199?A&A...315?.237?

SAO/NASA ADS Astronomy Abstract Service

Title:
Detection of far-infrared rotational lines of water vapour toward W Hydrae.

Authors:
Neufeld, D. A.; Chen, W.; Melnick, G. J.; de Graauw, T.; Feuchtgruber, H.; Haser, L.; Lutz, D.; Harwit, M.

Publication:
Astronomy and Astrophysics, v.315, p.L237-L240 (A&A Homepage)

Publication Date:
11/1996

Origin:
A&A via CDS

A&A Keywords:
STARS: CIRCUMSTELLAR MATTER, STARS: LATE-TYPE, INFRARED: STARS, MOLECULAR PROCESSES

Bibliographic Code:
1996A&A...315L.237N

Abstract

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 7_25_-6_16_line at 29.84μm, the 4_41_-3_12_line at 31.77μm, and the 4_32_-3_03_ line at 40.69μm. One additional emission line, the 4_41_-4_14_line 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^-19^W.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^-5^M_sun_/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.

Title:		1.8 MeV line emission from the Cygnus region.
Authors:		del Rio, E.; von Ballmoos, P.; Bennett, K.; Bloemen, H.; Diehl, R.; Hermsen, W.; Knoedlseder, J.; Oberlack, U.; Ryan, J.; Schoenfelder, V.; Winkler, C.
Publication:		Astronomy and Astrophysics, v.315, p.237-242 (A&A Homepage)
Publication Date:		11/1996
Origin:		A&A via CDS
A&A Keywords:		GAMMA RAYS: OBSERVATIONS, ISM: SUPERNOVA REMNANTS, STARS: WOLF-RAYET
Bibliographic Code:		1996A&A...315..237D

Abstract

Significant 1.8 MeV emission from the Cygnus region, attributed to the decay of radioactive ^26^Al, has been detected by COMPTEL. The COMPTEL sky-map shows diffuse, localized emission from this region with an integrated flux of (7.0+/-1.4).10^-5^photons/cm^2^/s at a significance level of 5σ. A study of ^26^Al candidate sources in the Cygnus region results in a 1.8MeV emission model that agrees well with the observed structure and intensity. Our analysis indicates that in the Cygnus region ^26^Al has mainly been produced by the combined nucleosynthesis activity of numerous young massive objects such as Wolf-Rayet stars and core collapse supernovae.

Title:		Detection of far-infrared rotational lines of water vapour toward W Hydrae.
Authors:		Neufeld, D. A.; Chen, W.; Melnick, G. J.; de Graauw, T.; Feuchtgruber, H.; Haser, L.; Lutz, D.; Harwit, M.
Publication:		Astronomy and Astrophysics, v.315, p.L237-L240 (A&A Homepage)
Publication Date:		11/1996
Origin:		A&A via CDS
A&A Keywords:		STARS: CIRCUMSTELLAR MATTER, STARS: LATE-TYPE, INFRARED: STARS, MOLECULAR PROCESSES
Bibliographic Code:		1996A&A...315L.237N