Electronic Telegram No. 4366
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 C/2017 D2 (BARROS)
     C. Jacques (Belo Horizonte, MG, Brazil) reports the discovery of a comet
by J. Barros on CCD images taken by Jacques, E. Pimentel, and Barros on Feb.
23 with a 0.45-m f/2.9 reflector at the SONEAR Observatory at Oliveira
(discovery observations tabulated below), the comet showing a condensed coma
with a diameter of 10".

     2017 UT             R.A. (2000) Decl.       Mag.   Observer
     Feb. 23.30751   19 02 43.85   -48 11 58.0   17.4   Jacques
          23.31674   19 02 45.21   -48 11 57.3   17.4     "
          23.32596   19 02 46.58   -48 11 56.5   17.4     "

Fifteen stacked 60-s follow-up observations by Jacques et al. on Feb. 23.8 UT
with an iTelescope 0.70-m f/6.6 astrograph at Siding Spring show a condensed
coma with a diameter of 11" and red mag 16.5-18.1.
     After the comet was posted on the Minor Planet Center's PCCP webpage,
other CCD astrometrists reported on the cometary appearance.  A. C. Gilmore
reports that observations obtained by P. M. Kilmartin and himself on Feb.
23.65-23.66 UT with the Mount John 1.0-m f/7.7 reflector show no obvious
coma but a 30" tail in p.a. 250 degrees in a stack of five 60-s exposures;
additional Mount John images on Feb. 26.67 show a well-condensed comet with
a similar tail.  H. Sato, Tokyo, Japan, writes that images taken with an
iTelescope 0.51-m f/6.8 astrograph (+ luminance filter) at Siding Spring on
Feb. 24.76 show the comet to be strongly condensed with a round coma 8" in
diameter, with no tail in eight stacked 60-s exposures; the w-band magnitude
was 17.3 as measured within a circular aperture of radius 4".9.
          The available astrometry (spanning Feb. 23-28), the following
preliminary parabolic orbital elements by Williams, and an ephemeris appear
on MPEC 2017-E05.

     T = 2017 July 12.2327 TT         Peri. = 333.3196
                                      Node  = 331.0942  2000.0
     q = 2.504125 AU                  Incl. =  31.2568


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2017 CBAT
2017 March 1                     (CBET 4366)              Daniel W. E. Green