Water late type stars

Water Signatures in Spectra of Late Type Stars and the Sun 169... 

A 22 GHz ortho-water maser in a dusty medium near late-type stars depends on several factors exchange of energy between dust and gas in the radiation field of a star, radiative cooling by water molecules and pumping of water masers (Babkovskaia, Poutanen, 2006 [14]). 

Supernova remnants sometimes show water emission (shock excited, e.g. in the supernova remnant 3 C 391, Reach and Rho, 1998 [277]). Woodall and Gray, 2007 [364] investigated 18 known supernova remnants for evidence of the 22.235-GHz water maser spectral line, using the 20-m telescope at the Onsala observatory in Sweden. Their results were negative, which was consistent with their theoretical models. Only in unusual environments can 22-GHz water masers be detected around supernova remnants. The Very Large Array was also used to search for water masers in the three supernova remnants W28, W44, and IC 443. Only one candidate maser was detected, in W44. Follow-up observations using the VLA at 1612 MHz demonstrate that the water maser in W44 is likely associated with a late-type star and not a shock in the supernova remnant (Claussen et al., 1999 [70]). 

Babkovskaia, N., Poutanen, J. A self-consistent model of a 22 GHz water maser in a dusty environment near late-type stars. Astron. Astrophys. 447,949-962 (2006)... 

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