Electronic Telegram No. 4271
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau@eps.harvard.edu (alternate cbat@iau.org)
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Prepared using the Tamkin Foundation Computer Network


COMET 252P/LINEAR
     M. Knight, University of Maryland; and D. Schleicher, Lowell Observatory,
report on imaging of comet 252P/LINEAR obtained from Apr. 2-7 using the
Lowell Observatory's 4.3-m Discovery Channel telescope, the Hall 1.1-m
telescope, and the 0.8-m telescope.  Comet 252P exhibited distinctly different
coma morphology between dust and gas species.  Enhanced images reveal a short
sunward dust feature and the dust tail.  Enhanced CN and C_3 images exhibited
a tilted spiral that is seen partially edge on approximately in the north-
south direction.  Enhanced OH images are also brightest along this direction
but with considerably more material in the tailward hemisphere, potentially
implying icy grains subject to radiation pressure.  The CN coma morphology
varied smoothly during a night and repeated approximately every 22 hr,
implying a period of about 22 hr or a sub-multiple thereof.  There is also a
repetition of features after about 95.5 hr, implying that the actual period
is 7.35 +/- 0.05 hr.

     Additional visual total-magnitude and coma-diameter estimates (cf. CBET
4268):  Mar. 17.13, 5.9, 30' (W. Souza, Sao Paulo, Brazil, 0.1-m refractor);
18.22, 5.3, 45' (M. Goiato, Aracatuba, Brazil, 7x50 binoculars); 19.28, 5.0,
60' (Goiato; mag about 4.7 via naked eye); 20.23, 4.9, about 60' (Souza);
21.33, 4.5, 90' (Goiato); 28.17, 6.0, 30' (Goiato; moonlight); Apr. 1.07,
5.4, 45' (J. J. Gonzalez, Leon, Spain, 6x50 monocular; visible to naked eye);
1.77, 5.5, 35' (K. Yoshimoto, Yamaguchi, Japan, 8x42 binoculars); 5.19, 5.7,
40' (Goiato); 7.05, 5.6, 35' (Gonzalez; mag about 5.2 to naked eye); 8.65,
6.3, 30' (S. Yoshida, Ibaraki, Japan, 10x70 refractor); 10.20, 5.9, 45'
(Souza, Amparo, Brazil, 10x50 binoculars).


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2016 CBAT
2016 April 12                    (CBET 4271)              Daniel W. E. Green