[Iaude] CBET 4583: 20181216 : COMET C/2018 X2 (FITZSIMMONS)

quai at eps.harvard.edu quai at eps.harvard.edu
Sat Dec 15 21:55:54 EST 2018

                                                  Electronic Telegram No. 4583
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau at eps.harvard.edu (alternate cbat at iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network

     A comet with an 8"-10" coma has been found by Alan Fitzsimmons in
stacked images obtained on Nov. 8.5 UT with a 0.5-m f/2 Schmidt reflector
at Haleakala in the course of the "Asteroid Terrestrial-impact Last Alert
System" (ATLAS) search program; the astrometry is tabulated below.

     2018 UT             R.A. (2000) Decl.       Mag.   Observer
     Dec.  8.46539    4 03 17.97   +54 03 05.1   19.1   Fitzsimmons
           8.47818    4 03 17.13   +54 03 01.4   19.2     "
           8.48597    4 03 16.60   +54 03 03.7   19.4     "
           8.49597    4 03 15.80   +54 03 01.6   19.0     "

After the object was posted on the Minor Planet Center's NEOCP and PCCP
webpages, other CCD astrometrists also reported on the cometary appearance.
R. Weryk, Institute for Astronomy, University of Hawaii, writes that three
60-s gri-band exposures were obtained on Dec. 9.4 UT with the 3.6-m
Canada-France-Hawaii Telescope via R. Wainscoat, C. Crowder, and T. Burdullis,
which show an obvious tail extending almost directly south for about 10"; the
coma was slightly larger than neighboring stars (full-width-at-half-maximum
1".3, vs. 0".77).  H. Sato, Tokyo, Japan, finds a strongly condensed, disk-
like coma 12" in diameter on nine stacked 60-s exposures taken remotely on
Dec. 12.25 with an iTelescope 0.43-m f/6.8 astrograph near Mayhill, NM, USA;
there was no obvious tail, and the magnitude was 18.1 as measured within a
circular aperture of radius 7".6.  K. Sarneczky, Konkoly Observatory, reports
that six stacked 120-s unfiltered images taken with the 0.60-m Schmidt
telescope at Piszkesteto, Hungary, on Dec. 10.9 shows a strongly condensed
coma 6" in diameter with a 10" tail in p.a. 180 deg.  Five stacked 120-s
unfiltered images taken on Dec. 11.86 by G. Favero and R. Furgoni with a
0.80-m f/4 reflector at the Osservatorio del Celado, Castello Tesino, Italy,
show a very faint coma of red mag 17.8-17.9 and a hint of a tail of about 15"
long in p.a. 180 deg.  L. Buzzi, Varese, Italy, notes that stacked images
obtained on Dec. 15.1 with a 0.60-m f/4.64 reflector show a compact coma
10" wide and a broad tail at least 13" long centered at p.a. 177 deg.
     The available astrometry, the following preliminary nearly parabolic
orbital elements by G. V. Williams (from 83 observations spanning Dec. 8-15),
and an ephemeris appear on MPEC 2018-X135.

                    Epoch = 2019 July 16.0 TT
     T = 2019 July  8.8444 TT         Peri. = 162.0717
     e = 0.985672                     Node  = 340.8413  2000.0
     q = 2.126778 AU                  Incl. =  23.0760

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

                         (C) Copyright 2018 CBAT
2018 December 16                 (CBET 4583)              Daniel W. E. Green

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