[Iaude] CBET 4574: 20181120 : COMET C/2018 U1 (LEMMON)

quai at eps.harvard.edu quai at eps.harvard.edu
Tue Nov 20 11:55:16 EST 2018


                                                  Electronic Telegram No. 4574
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


COMET C/2018 U1 (LEMMON)
     An apparently asteroidal object that was found on images obtained by
R. A. Kowalski with the Mount Lemmon Survey's 1.5-m reflector (discovery
observations tabulated below) was reported as having cometary appearance by
CCD astrometrists elsewhere after it was posted on the Minor Planet Center's
PCCP webpage as a result of its comet-like orbit.

     2018 UT             R.A. (2000) Decl.       Mag.   Observer
     Oct. 27.18558   19 15 18.62   +52 24 47.3   20.0   Kowalski
          27.19084   19 15 18.60   +52 24 45.0   20.0     "
          27.19612   19 15 18.62   +52 24 42.0   20.0     "
          27.24030   19 15 18.84   +52 24 21.2   20.2     "
          27.24584   19 15 18.94   +52 24 18.7   19.9     "
          27.25232   19 15 18.89   +52 24 15.4   20.6     "
          27.25850   19 15 18.82   +52 24 12.5   20.8     "

Images taken by W. R. Ryan and E. V. Ryan on Oct. 27.24-27.28 UT with a 2.4-m
reflector at Magdalena Ridge Observatory (near Socorro, NM) show a "subtle
cometary appearance", with follow-up observations on Nov. 19.1 showing a
slightly elongated coma or tail in p.a. 35 deg.  H. Sato, Tokyo, Japan, writes
that fourteen stacked 60-s exposures taken on Oct. 29.1 with an iTelescope
0.43-m f/6.8 astrograph near Mayhill, NM, USA, show a starlike head but a
hint of at tail 5" long toward p.a. 270 degrees; the total magnitude was 19.9
as measured within a circular aperture of radius 5".7.  K. Sarneczky and A.
Ordasi, Konkoly Observatory, note that eight stacked 120-s unfiltered images
taken with the 0.60-m Schmidt telescope at Piszkesteto, Hungary, on Nov. 4.8
show a nearly stellar coma and a faint, short tail in p.a. 70-80 deg.
     The available astrometry, the following preliminary hyperbolic orbital
elements by G. V. Williams (from 159 observations spanning Oct. 27-Nov. 20),
and an ephemeris appear on MPEC 2018-W42.

                    Epoch = 2021 Nov.  2.0 TT
     T = 2021 Nov.  1.4854 TT         Peri. = 180.5330
     e = 1.004072                     Node  =  75.4867  2000.0
     q = 4.981679 AU                  Incl. = 108.2982


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2018 CBAT
2018 November 20                 (CBET 4574)              Daniel W. E. Green



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