essence a subset of detected interstellar molecules. About 200 species have been
detected in the interstellar medium with lists being curated at several sites.
5 The
abundances measured in comets are generally comparable to those measured in starforming regions, suggesting that comets contain preserved material from the presolar
nebula (Biver and Bockelée-Morvan 2019).
Molecular abundances relative to water measured in comae do show strong
variations from comet to comet. (Variations with heliocentric distance will be
discussed in Sect. 3.6). An example of this is given in Table 3.6 which gives the
Fig. 3.18 Remote sensing detection of molecules from many comets compared to the detections
made by the ROSINA experiment at 67P. Ground-based values are shown by the black bars. The
minimum values of all detected species are shown with the diamond. The grey bars show the
ROSINA values from Table 3.1 where the bar indicates a range for the northern to southern
hemisphere measurements. (Data from Le Roy et al. 2015, Rubin et al. 2019 and Bockelée-Morvan
and Biver 2017)
5 https://science.gsfc.nasa.gov/691/cosmicice/interstellar.html is an example.
3.3 Minor Species
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