Comet 252P/LINEAR

I. Coulson, East Asian Observatory, Hilo; Y.-J. Kuan, W. Ip, Z.-Y. Lin, W.-L. Tseng, and Y.-L. Chuang, National Taiwan Normal University; and S. Milam, S. Charnley, and M. Cordiner, Goddard Space Flight Center, NASA, write that they obtained a 40-min- duration, 900"-wide, 850-micron image of comet 252P with the SCUBA-2 continuum camera on the James Clerk Maxwell Telescope (JCMT) on Mar. 25.66 UT, when the comet was at distances r = 1.007 and Decl. = 0.0435 AU. The comet's image is centrally condensed and slightly larger than the FWHM of the JCMT beam of 15", which corresponds to 475 km at the comet. The integrated brightness is 158 +/- 28 mJy, implying a mass of about 1-mm-sized dust particles of 1.2 x 10**8 kg. The simultaneous 450-micron brightness is less than 930 mJy (3-sigma). Observations with the HARP array receiver on Mar. 27 and 28 show J=4-3 HCN emissions to have peak values of T***_a about 1 K, FWHMs of 1 km/s, and with variable profile and strength. Integrated flux maps show the comet is again slightly larger than the JCMT beam. Deduced production rates of HCN and water are typically 3.3 x 10**25 and 1.7 x 10**28 molecules/s.