COMET LEVY (1990C) - GROUNDBASED PHOTOMETRIC RESULTS

Narrowband filter photometry of Comet Levy (1990c) was obtained on 51 nights in the interval from 3 June 1990 to 19 April 1991. The emission bands of OH, NH, CN, C3, and C2 were isolated, in addition to continuum points at 3650 and 4845 Å. Relative abundances among the species were typical of most comets previously observed. All species showed pronounced asymmetry about perihelion, with production rates for most species being about twice as large before perihelion as after over the heliocentric distance range of 1.0-3.0 AU. The OH production rate's asymmetry was nearly double that observed for the other species, with maximum production occuring more than a month before other species. Periodic variations having a single-peaked lightcurve period of 18.9 hr or a double-peaked lightcurve period of 37.8 hr were observed during late-August 1990. Observations by Feldman et al. (1991) only 3 weeks later using the IUE satellite require a period 7% shorter than the value we found. Neither period determination is consistent with both data sets, implying that the rotational period charged between the two sets of observations. © 1991.