Narrowband photometric results for comet 46 P / Wirtanen

Narrowband filter photometry was performed on the Rosetta spacecraft target, comet 46P/Wirtanen, at Lowell Observatory in 1991 and 1997. Production rates were determined for OH, NH, CN, C 3 , and C 2 , along with a measure of the dust production, A(θ)fρ. Relative abundances were computed, and a comparison to other comets indicates that this comet has a " typical " composition and a very low dust-togas ratio. The peak value of A(θ)fρ was 138 cm, while the OH production rates, used in conjunction with a standard water production model, yield a peak water production of ∼1.0×10 28 mol s −1 at perihelion and suggest a minimum active surface area of ∼1.8 km 2. Finally, a comparison to comet Halley puts Wirtanen into context with previous in situ comet measurements.