I held out, but ultimately May is not a rich month for Monthly Notices of the Royal Astronomical Society (vol. 530, #1):
Aravind, K. et al. Optical spectroscopy of comets using Hanle Echelle Spectrograph (HESP) p. 393–404 stae666
We don’t have a lot of comet missions, due to the eccentricity and inclination of their orbits making them costly in terms of propulsion. We have telescopes, but… we don’t have a lot of compositional information, due to the rather featureless comet spectra in the range visible to human eyes (and therefore most telescopes). This is how the “icy snowball” caricature of comets took hold, and still won’t die: without good information, bad (or mediocre- not that good either) information can take hold… and won’t die. Ground telescopes happen to be relevant, even in the “Space Age,” because probe missions, limited by flight mass and rocket fairing volume, cannot pack high-resolution spectrographs, with long light paths and their fine composition sensitivities. This new work does not exceed prior work in range (i. e., longer infrared wavelengths beyond 1000 μm) and therefore doesn’t spot any new components. But the Hanle instrument is quite long and hi-res, demonstrating its contribution on water (true H2O/OH) and the similar components in the “visible” (<1000 μm) range.