Electronic Telegram No. 3257
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


COMET 168P/HERGENROTHER
     David Schleicher, Lowell Observatory, reports that he obtained five sets
of narrowband photometry of comet 168P on Oct. 9 (when r = 1.42 AU and Delta
= 0.45 AU) using the Hall 1.1-m telescope at Lowell Observatory, resulting in
the following averaged production rates:  log Q(OH) = 27.85; equivalent log
Q(water; vectorial) = 27.91; log Q(NH) = 25.01; log Q(CN) = 25.33; log Q(C_2)
= 24.52; log Q(C_3) = 23.77; log [Af(rho)] at 526.0 nm = 2.5 (cf. IAUC 7342).
These measurements reveal that the comet is strongly carbon-chain depleted
(cf. A'Hearn et al. 1995, Icarus 118, 223), by even more than that of comet
21P/Giacobini-Zinner, the proto-type of this class.

     Visual total-magnitude and coma-diameter estimates:  Sept. 6.90 UT, 11.2,
3'.5 (J. J. Gonzalez, Leon, Spain, 0.20-m reflector); 13.90, 11.7, 2' (U.
Pilz, Leipzig, Germany, 32-cm reflector); 24.79, 10.4, 1'.0 (K. Yoshimoto,
Yamaguchi, Japan, 0.25-m reflector); Oct. 5.78, 9.5, 3' (T. Karhula, Virsbo,
Sweden, 18x50 binoculars); 6.81, 9.5, 3' (J. Warell, Lindby, Skurup, Sweden,
11x80 binoculars); 9.58, 9.4, 3' (Yoshimoto, 20x100 binoculars); 13.52, 10.1,
2'.1 (Y. Nagai, Niigata, Japan, 0.32-m reflector).


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2012 CBAT
2012 October 18                  (CBET 3257)              Daniel W. E. Green