Measurement of Water Vapor and Oxygen Abundances

scientific abstract earth.s atmosphere is so rich in water vapor, that radiation having wavelengths anywhere near a lowlying water vapor transition is completely absorbed in relatively thin layers of air. with iso well above these atmospheric layers, we propose to search for lowlying transitions of water vapor in interstellar clouds, particularly in shocked regions, and in the extended atmospheres of oxygenrich stars. such regions are characterized by densities and temperatures sufficiently high to (1) chemically drive a large fraction of the available oxygen into water, and (2) excite highlying transitions. detecting a high abundance of water in interstellar molecular clouds could account for the surprisingly low oxygentocarbon ratio observed in other chemical species in those clouds, and thereby resolve a major puzzle of cosmic chemical abundance ratios. for m42 and vy cma on a spring launch, or alternatively w49 and w hya, for a launch in the fall, we will also seek to measure the abundance of molecular oxygen. observation summary we will make use of fabryperot observations, at short wavelengths, as well as long, making use of aots lws04 and sws07. with lws, we will establish a continuum base by observing four elements each side of the line, and make observations at two steps per resolution element. we will aim for a signal to noise ratio of about 10 on individual spectral lines, but will set a maximum duration on the observation of individual scans of about 18000 sec. for stellar observations, line strength variability may be expected and the observations on any given star will need to be concatenated, so as to fall within a given 24 hour orbit. since pointing at precisely the same location may be a problem on successive orbits, and shocked regions are complex, we will also concatenate the line observations for any given shocked region. in no case, however, will the duration of a concatenated obs trunca [truncated!, Please see actual data for full text]