Electronic Telegram No. 4396
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)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


COMET P/2017 K3 (GASPAROVIC)
     Goran Gasparovic, Zagreb, Croatia, reports the discovery of a comet with
a faint coma visible on CCD images taken by Y. Chen and himself with an
iTelescope 0.50-m f/6.8 reflector at Siding Spring on May 22, with confirming
observations obtained two nights later with an iTelescope 0.43-m f/6.8
reflector also at Siding Spring (as tabulated below).

     2017 UT             R.A. (2000) Decl.       Mag.   Observer
     May  22.59653   16 13 48.51   -28 23 37.6   19.4   Gasparovic
          22.61352   16 13 47.98   -28 23 36.6            "
          22.62973   16 13 47.45   -28 23 37.0   19.4     "
          24.46693   16 12 46.69   -28 23 31.2   19.5     "
          24.48019   16 12 46.24   -28 23 30.8   19.7     "
          24.49356   16 12 45.66   -28 23 31.5   19.8     "

After the comet was posted on the Minor Planet Center's PCCP webpage, M.
Kusiak (Zywiec, Poland) communicated that pre-discovery CCD images taken by
M. Gedek, M. Zolnowski, R. Reszelewski, and himself with a 0.25-m f/3.6
reflector at the Polonia Observatory at San Pedro de Atacama, Chile, on May
21.1 UT show the object to be slightly diffuse with coma size 8" in 3".5
seeing, the total magnitude being 18.7-19.6.  H. Sato, Tokyo, Japan, writes
that eight stacked 60-s exposures taken on May 26.5 with a 0.51-m f/6.8
astrograph at Siding Spring show a strongly condensed coma 10" in diameter
with a hint of tail 10" long toward p.a. 300 degrees; the w-band magnitude
was 18.3 as measured within a circular aperture of radius 6".6.  Unfiltered
images taken by A. Maury, J.-B. Vanssay, and J.-F. Soulier with a 0.4-m
f/5.4 Ritchey-Chretien reflector at San Pedro de Atacama, Chile, on May
30.15-30.19 show a coma about 11" in size with a tail about 13" long in
p.a. 300-350 deg; the magnitude was 18.9 in an aperture of radius 6".1.
     The available astrometry, the following preliminary elliptical orbital
elements (from 67 observations spanning May 21-June 1; mean residual 0".6) by
G. V. Williams, and an ephemeris appear on MPEC 2017-L03.

                    Epoch = 2017 June 16.0 TT
     T = 2017 June  2.8742 TT         Peri. = 254.4823
     e = 0.577654                     Node  = 353.9068  2000.0
     q = 2.315355 AU                  Incl. =   4.2429
       a =  5.482128 AU    n = 0.0767857    P =  12.84 years


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

                         (C) Copyright 2017 CBAT
2017 June 1                      (CBET 4396)              Daniel W. E. Green