Comparing CN Features in Two Comets: 1P/Halley and 103P/Hartley 2

Comets 1P/Halley and 103P/Hartley 2 show distinct CN features in their respecive comae. Both comets are non-principal-axis rotators. 1P/Halley is the proto-type for Halley-type comets with the Oort Cloud as its possible source region, whereas 103P/Hartley 2 is a Jupiter-Family comet that possibly originated from the Kuiper Belt. Both comets were spacecraft targets and studied widely from both space and from the ground.We will discuss the properties of CN features, and in particular the behavior of the derived outflow velocities based on the CN features present in the groundbased coma images of these two comets. The corresponding heliocentric distances for CN images of comet 1P/Halley range from approximately 0.8 AU to 2.0 AU (during its post-perihelion leg of the 1986 apparition). For CN images of comet 103P/Hartley 2, the corresponding heliocentric distances range from 1.31 AU through the perihelion (at 1.06 AU) to 1.25 AU (during its 2010 apparition).Ultimately, these results will be used to understand the rotational states and the activity behaviors of these two comets.