The main objective of the proposed research project is the search for
 distributed sources in cometary comae and the study of their physical
 and chemical properties. Distinct evidence for the existance of such
 distributed sources for volatile material in comets has been found for
 comet Halley in 1986, from which new concepts on cometary processes
 emerged. It is now widely believed that a significant portion of the
 volatiles in comets originate directly from grains that contain a
 certain amount of organic molecules.
 These organics as well as some of the most abundant gaseous parent
 molecules known in comets have no observable bands in the visible.
 Their fundamental vibrational bands lie in regions in the near-IR
 where ground-based observations are either impossible or extremely
 difficult because of the atmospheric absorption. However, direct
 imaging of the inner coma of a comet with near-IR filters that reflect
 a substancial part of the parent molecules presently known to exist
 is imperative to distinguish between species originating exclusively
 at the nucleus and species that are at least partially produced from
 grains. At present almost nothing is known about the possible ejection
 mechanism of volatiles from grains. Observational data are therefore
 urgently needed to determine the basic properties of distributed
 sources like their extension and their main compounds. The data that
 are proposed to be collected here would provide two-dimensional
 spatial profiles of the species most relevant to the problem from
 which their production/destruction mechanisms can be modeled.