[Iaude] CBET 4521: 20180609 : COMET P/2018 L1 (PANSTARRS)

quai at eps.harvard.edu quai at eps.harvard.edu
Fri Jun 8 16:38:59 EDT 2018

                                                  Electronic Telegram No. 4521
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

     Another comet has been discovered on images taken on June 3.3 UT with
the 1.8-m Pan-STARRS1 Ritchey-Chretien telescope at Haleakala (discovery
observations tabulated below); R. Weryk, Institute for Astronomy, University
of Hawaii, writes that one of the three images showed a short 5" tail toward
the southeast, and the comet's head had a full-width-at-half-maximum of about
1".5 in 1".1 seeing.  Weryk arranged for 60-s gri-band follow-up images to
be taken by R. Wainscoat, C. Wipper, and A. Petric with the 3.6-m Canada-
France-Hawaii Telescope at Mauna Kea on June 6.34, which show the object to
be clearly a comet, with a tail extending for about 6" in p.a. 100 degrees;
the comet's FWHM was about 1".4 in 1".0 seeing, and the magnitude was measured
to be 19.7.

     2018 UT             R.A. (2000) Decl.       Mag.
     June  3.28457   13 04 11.55   -19 27 54.1   20.0
           3.29557   13 04 11.56   -19 27 49.4   19.9
           3.30658   13 04 11.57   -19 27 44.7   20.0

After the comet was posted on the Minor Planet Center's PCCP webpage, other
CCD astrometrists also commented on the object's cometary appearance.
G. Hug, Scranton, KS, USA, reports that images taken on June 4.13-4.16 UT
with a 0.56-m reflector show a diffuse circular coma of diameter 8"-10" and
mag 18.5-18.9.  H. Sato, Tokyo, Japan, stacked ten 60-s exposures taken on
June 4.49-4.50 with an iTelescope 0.51-m f/6.8 astrograph at Siding Spring
to find a strongly condensed coma 8" in diameter with no tail; the total
magnitude was 18.8 as measured within a circular aperture of radius 4".9.
     The available astrometry (including apparently asteroidal pre-discovery
Mount Lemmon observations from May 18.2 UT, when the magnitude was measured
to be 18.8-19.2), the following elliptical orbital elements by G. V. Williams
(from 36 observations spanning May 18-June 7; mean residual 0".4), and an
ephemeris appear on MPEC 2018-L36.

                    Epoch = 2018 Nov. 18.0 TT
     T = 2018 Nov. 12.5659 TT         Peri. =  17.8640
     e = 0.481593                     Node  = 268.6758  2000.0
     q = 1.885474 AU                  Incl. =  10.5849
       a =  3.637050 AU    n = 0.1420955    P =   6.94 years

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

                         (C) Copyright 2018 CBAT
2018 June 9                      (CBET 4521)              Daniel W. E. Green

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