Comet 46P/WIRTANEN

E. Jehin, Y. Moulane, J. Manfroid, and F. Pozuelos, STAR Institute, University of Liege, report on observations made of comet 46P with the 0.60-m Ritchey-Chretien telescopes at the Oukaimeden Observatory in Morocco (during Dec. 9.77-10.08 UT) and at La Silla in Chile (during Dec. 10.04-10.29); a total of 12.5 hours of images were obtained continuously through CN and C_2 filters. An exposure time of 300 s was used for each filter. After data reduction and flux calibration, aperture photometry was performed with a 20" aperture (as well as 10" and 50"), revealing a very clear periodic signal in the CN data with two maxima and two assymetric minima. The CN datasets from each telescope were phased very well, with a best period of 0.383 day or 9.19 hr, matching data obtained on several nights around this tiime (the Fourier peak giving an uncertainty of 0.002 day on the whole interval). The CN phase diagram shows an amplitude of about 0.24 magnitude. The C_2 periodic signal is, however, not that clear, and no value has been derived so far.