Daughter Molecule, Comet
A daughter molecule is a molecule produced from the photodissociation of a parent molecule which is directly outgassed from a cometary nucleus. The most abundant parent molecule is H2O; its dissociation products are H and OH. Other parent molecules include CO, CO2, CH4, NH3, HCN, H2CO, and H2S. Daughter molecules include CN, CS, and CO (which appears to be both a parent and a daughter molecule). Daughter molecules and radicals are mostly detected from their visible and ultraviolet spectra, while parent molecules are better observed with IR and millimeter spectroscopy.