[Iaude] CBET 4487: 20180211 : COMET P/2018 C1 (LEMMON-READ)

quai at eps.harvard.edu quai at eps.harvard.edu
Sat Feb 10 21:22:55 EST 2018


                                                  Electronic Telegram No. 4487
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 P/2018 C1 (LEMMON-READ)
     Mike T. Read reports his discovery of a comet on CCD mosaic images
obtained on Feb. 9.3 UT with the Spacewatch 0.9-m f/3 reflector at Kitt Peak,
noting a possible faint, broad tail 10" long in p.a. 300 degrees on the three
169-s exposures.  Follow-up observations by Read with the Spacewatch 1.8-m
f/2.7 reflector on Feb. 10.3 also show the faint tail in mediocre (2".1)
seeing:  he describes it as very faint, wide, and diffuse, but a definite
tail over 10" long in p.a. 300 deg.  G. V. Williams, Minor Planet Center,
notes that the object had also been discovered as apparently asteroidal in
Mt. Lemmon Survey images obtained on Feb. 4.4; it was sent as a possible
near-earth object but was not posted to the MPC's NEOCP webpage at that time.
Both sets of discovery observations are tabulated below.

     2018 UT             R.A. (2000) Decl.       Mag.   Observer
     Feb.  4.41871    9 23 33.88   + 8 50 22.5   19.1   Johnson
           4.42384    9 23 33.66   + 8 50 22.6   18.9     "
           4.45096    9 23 32.65   + 8 50 24.1   19.2     "
           4.45610    9 23 32.44   + 8 50 24.4   18.7     "
           9.28990    9 20 34.45   + 8 55 19.0   19.1   Read
           9.30549    9 20 33.90   + 8 55 20.4   19.1     "
           9.32107    9 20 33.31   + 8 55 21.3   19.3     "

After the object was posted to the MPC's PCCP webpage, R. Weryk found the
comet in Pan-STARRS1 images taken with the 1.8-m Ritchey-Chretien reflector
at Haleakala on Jan. 16.42-16.45 UT, noting that it showed a very obvious
tail extending almost due west for about 6"; the w-band magnitude was
measured to be 20.6, and the image showed a full-width-at-half-maximum of
about 1".1 in 0".7 seeing.  H. Sato, Tokyo, Japan, writes that ten stacked
60-s exposures taken with an iTelescope 0.43-m f/6.8 astrograph on Feb. 10.27
show a moderately condensed coma 8" in diameter with no obvious tail; the
w-band magnitude was 19.0 as measured within a circular aperture of radius
5".7.
     The available astrometry, the following elliptical orbital elements by
G. V. Williams (from 42 observations spanning Jan. 16-Feb. 10), and an
ephemeris appear on MPEC 2018-C77.

                    Epoch = 2018 Feb. 11.0 TT
     T = 2018 Feb. 25.1543 TT         Peri. = 234.2401
     e = 0.534334                     Node  = 270.4217  2000.0
     q = 2.594433 AU                  Incl. =   5.1296
       a =  5.571447 AU    n = 0.0749466    P =  13.15 years


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

                         (C) Copyright 2018 CBAT
2018 February 11                 (CBET 4487)              Daniel W. E. Green



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