  Observations of carbon monosulfide (CS), a possible photodissociation
fragment of CS$_2$, has a long history serving as a remote proxy for atomic
sulfur, and more broadly, one of the sulfur reservoirs in cometary bodies.
Interpretations of CS fluorescence emissions in ultraviolet observations of
comets have, to-date, relied on a murky and ill-documented lineage of
calculations for CS fluorescence efficiencies that can be difficult to assess.
We report new fluorescence efficiencies of the CS radical, utilizing a
rovibrational structure with vibrational states up to $v = 8$ and rotational
states up to $N = 100$. A new set of band transition rates is produced through
benchmarking comparisons to laboratory electron impact experiments, and
subsequently utilized in the fluorescence calculations. We confirm historical
reports of the ultraviolet $(0,0)$ band fluorescence efficiency, and conclude
that blends and an expanded rovibrational structure have little impact on the
fluorescence properties. Combined, the present results affirm the accuracy of
the historical record of sulfur abundances derived via ultraviolet CS emissions
in cometary observations with e.g., IUE and HST. Benchmark comparisons to IUE
observations of comet Bradfield show favorable agreement with the theoretical
models. We expand the model to the time-domain, and find that thermalization of
the ground state and/or `hot' initial distributions of CS lead to noticable
changes in the shape of the $(0,0)$ band. The impact on existing sulfur
abundances derived via ultraviolet CS observations, and new connections to
sulfur reservoirs in protoplanetary disks are discussed. The model code and
computed fluorescence efficiencies are made publicly available.
