[Iaude] CBET 4549: 20180819 : COMET P/2018 P4 (PANSTARRS)

quai at eps.harvard.edu quai at eps.harvard.edu
Sat Aug 18 20:33:33 EDT 2018


                                                  Electronic Telegram No. 4549
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 P4 (PANSTARRS)
     R. Weryk, Institute for Astronomy, University of Hawaii reportsthe
discovery of another comet in CCD exposures taken with the 1.8-m Pan-STARRS1
Ritchey-Chretien telescope at Haleakala on Aug. 8 UT (discovery observations
tabulated below, together with prediscovery Pan-STARRS1 observations from
July 10); the comet's head showed a full-width-at-half-maximum of about 1".2
in seeing of about 1".0.

     2018 UT             R.A. (2000) Decl.       Mag.
     July 10.56729   23 57 12.14   - 6 06 59.9   21.6
          10.58904   23 57 12.31   - 6 06 54.5   21.5
          10.59984   23 57 12.40   - 6 06 51.7   21.5
     Aug.  8.50138   23 54 34.81   - 4 30 01.6   20.6
           8.51317   23 54 34.55   - 4 29 59.8   20.6
           8.52499   23 54 34.30   - 4 29 58.1   20.6
           8.53682   23 54 34.04   - 4 29 56.4   20.6

R. Wainscoat writes that he obtained three 40-s w-band follow-up observations
this object with the 3.6-m Canada-France-Hawaii Telescope at Mauna Kea (queue
observer D. Woodworth) on Aug. 10.55 UT; the observations were non-sidereally
tracked using the predicted motion of the comet, which showed FWHM = 0".95 in
0".7 seeing; the comet displayed a broad, low-surface-brightness tail at
position angle approximately 230 degrees, extending for approximately 15"
(measurement assisted by M. Micheli).
     After the comet was posted on the Minor Planet Center's PCCP webpage,
K. Sarneczky and O. Hanyecz, Konkoly Observatory, obtained six stacked 120-s
unfiltered CCD images with the 1.02-m Ritchey-Chretien telescope at
Piszkesteto, Hungary, on Aug. 18.0 UT, which show a nearly stellar coma and a
slightly curved tail extending about 15" long toward the southwest; the red
magnitude of the coma was 19.6 as measured within a circular aperture of
radius 2".8.
     The available astrometry, the following elliptical orbital elements by
G. V. Williams (from 33 observations spanning July 10-Aug. 18), and an
ephemeris appear on MPEC 2018-Q35.

                    Epoch = 2018 Nov. 18.0 TT
     T = 2018 Nov.  7.3033 TT         Peri. =   8.1087
     e = 0.449344                     Node  = 353.1102  2000.0
     q = 3.666068 AU                  Incl. =  23.1109
       a =  6.657636 AU    n = 0.0573752    P =  17.18 years


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

                         (C) Copyright 2018 CBAT
2018 August 19                   (CBET 4549)              Daniel W. E. Green



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