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We report on photometry and imaging of Comet 10P/Tempel 2 obtained at LowellObservatory from 1983 through 2011. We measured a nucleus rotation period of8.950 +/- 0.002 hr from 2010 September to 2011 January. This rotation period islonger than the period we previously measured in 1999, which was itself longerthan the period measured in 1988. A nearly linear jet was observed which variedlittle during a rotation cycle in both R and CN images acquired during the 1999and 2010 apparitions. We measured the projected direction of this jetthroughout the two apparitions and, under the assumption that the source regionof the jet was near the comet's pole, determined a rotational pole direction ofRA/Dec = 151deg/+59deg from CN measurements and RA/Dec = 173deg/+57deg fromdust measurements (we estimate a circular uncertainty of 3deg for CN and 4degfor dust). Different combinations of effects likely bias both gas and dustsolutions and we elected to average these solutions for a final pole of RA/Dec= 162 +/- 11deg/+58 +/- 1deg. Photoelectric photometry was acquired in 1983,1988, 1999/2000, and 2010/2011. The activity exhibited a steep turn-on ~3months prior to perihelion (the exact timing of which varies) and a relativelysmooth decline after perihelion. The activity during the 1999 and 2010apparitions was similar; limited data in 1983 and 1988 were systematicallyhigher and the difference cannot be explained entirely by the smallerperihelion distance. We measured a "typical" composition, in agreement withprevious investigators. Monte Carlo numerical modeling with our pole solutionbest replicated the observed coma morphology for a source region located near acomet latitude of +80deg and having a radius of ~10deg. Our model reproducedthe seasonal changes in activity, suggesting that the majority of Tempel 2'sactivity originates from a small active region located near the pole.

the astronomical journal

A Quarter-Century of Observations of Comet 10P/Tempel 2 at Lowell  Observatory: Continued Spin-Down, Coma Morphology, Production Rates, and  Numerical Modeling