Observations of the deuterated molecule , C D , can test and extend fractionation theories ( which explain the enhanced abundance of deuterated molecules in the interstellar medium ) .
Observations of multiple rotational transitions of C H can result in estimates of the local density and temperature .
Observations of the deuterated C H , C H   , can test and extend fractionation theories ( which explain the enhanced abundance of deuterated molecules in the interstellar medium ) .
Observations of multiple rotational transitions of C H can result in estimates of the local density and temperature .