THE ANOMALOUS MOLECULAR ABUNDANCES OF COMET P/WOLF-HARRINGTON

Narrowband filter photometry of Comet P/Wolf-Harrington was performed at Lowell Observatory during the comet's 1984 and 1990/1991 apparitions. A single spectrophotometric observation was also obtained in 1991 using the Multiple Mirror Telescope at Mt. Hopkins. Production rates of OH, CN, C2, C3, NH, and NH2 were derived from these data sets, and the quantity Afρ-a measure of the dust production-was also calculated. Relative abundances, expressed as ratios of production rates, were compared to those measured in other, "typical," comets. Comet Wolf-Harrington is shown to be depleted by over an order of magnitude in its pure carbon species when compared to OH (a measure of the water abundance) and to CN. Both NH and NH2 are also depleted, but apparently by a lesser amount. Similar abundance anomalies have been seen in Comet P/Giacobini-Zinner, but they are more extreme in Wolf-Harrington. Taken together, these data imply that a nonnegligible fraction of comets (or their constituent components) formed at a different temperature and, therefore, a different location and/or time than did the majority of comets. © 1993 by Academic Press, Inc.