[Iaude] CBET 4602: 20190117 : COMET P/2019 A6 (LEMMON-PANSTARRS)

quai at eps.harvard.edu quai at eps.harvard.edu
Thu Jan 17 14:28:58 EST 2019


                                                  Electronic Telegram No. 4602
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/2019 A6 (LEMMON-PANSTARRS)
     An apparently asteroidal object reported from observations obtained by
A. R. Gibbs and R. A. Kowalski with the Mt. Lemmon 1.5-m reflector on 2018
Dec. 14 and 19, respectively, and with the Pan-STARRS1 1.8-m Ritchey-Chretien
telescope at Haleakala on 2018 Dec. 16 and 2019 Jan. 7, has been found to
show cometary appearance; the first four nights of available astrometry are
tabulated below.  R. Weryk and R. Wainscoat, Institute for Astronomy,
University of Hawaii, reported that four w-band Pan-STARRS1 images taken on
Jan. 7.5 UT showed marginally that this might be a comet, with the image
having full-width-at-half-maximum of about 1".7 in the best seeing (1".4),
with a slight asymmetry suggesting a tail extending to the northwest.

     2018 UT             R.A. (2000) Decl.       Mag.   Observer
     Dec. 14.43864    9 17 54.34   - 2 09 12.9   20.4   Gibbs
          14.44460    9 17 54.25   - 2 09 21.0            "
          14.51767    9 17 52.72   - 2 10 55.3   20.6     "
          14.51877    9 17 52.72   - 2 10 56.7   20.5     "
          14.51987    9 17 52.68   - 2 10 58.0   20.4     "
          14.52097    9 17 52.67   - 2 10 59.6   20.5     "
          16.53584    9 17 11.14   - 2 54 09.3   20.4   Pan-STARRS1
          16.54823    9 17 10.81   - 2 54 25.0   20.2     "
          16.56060    9 17 10.51   - 2 54 40.8   20.7     "
          19.36815    9 15 58.65   - 3 53 57.7   20.5   Kowalski
          19.37335    9 15 58.46   - 3 54 04.1   20.5     "
          19.37854    9 15 58.32   - 3 54 10.9   20.2     "
          19.38376    9 15 58.18   - 3 54 16.6   20.9     "
     Jan.  7.51449    9 01 17.92   - 9 54 29.2   20.7   Pan-STARRS1
           7.52615    9 01 17.19   - 9 54 40.4   20.6     "
           7.53780    9 01 16.45   - 9 54 51.7   20.6     "
           7.54948    9 01 15.71   - 9 55 02.9   20.6     "

Weryk and Wainscoat obtained three 60-s confirming gri-band images with the
3.6-m Canada-France-Hawaii Telescope on 2019 Jan. 8.65 UT (queue observer D.
Woodworth, queue coordinator A. Petric), which show a very-low-surface-
brightness tail extending for at least 20" towards p.a. 320 degrees (not in
the direction of the comet's apparent motion); tracking was imperfect, but
they measured FHWM = 1".0 in 0".8 seeing.  Gibbs reported that sixteen
co-added 30-s CCD images obtained with the Steward Observatory's 1.0-m
reflector at Mt. Lemmon in poor transparency on Jan. 9.4 show a 5" tail in
p.a. 315 deg.  After the object was posted on the Minor Planet Center's PCCP
webpage, CCD astrometrists elsewhere also reported on the cometary appearance.
H. Sato, Tokyo, Japan, writes that twelve stacked 60-s exposures taken on
Jan. 8.6 with an iTelescope 0.51-m f/6.8 astrograph at Siding Spring show a
strongly condensed coma 10" in diameter with a hint of tail 10" long toward
p.a. 50 degrees; the magnitude was 19.5 as measured within a circular
aperture of radius 6".5.  R. S. McMillan found a 3" tail pointed northward
on R-band images obtained in 2".5 seeing with the Spacewatch II 1.8-m f/2.7
reflector at Kitt Peak on Jan. 17.3.
     The available astrometry, the following elliptical orbital elements
by G. V. Williams (from 49 observations spanning 2018 Dec. 14-2019 Jan.
17), and an ephemeris appear on MPEC 2019-B46.

                    Epoch = 2018 Aug. 30.0 TT
     T = 2018 Aug. 29.3254 TT         Peri. = 156.3002
     e = 0.639361                     Node  = 280.2649  2000.0
     q = 1.938103 AU                  Incl. =  33.2210
       a =  5.374083 AU    n = 0.0791129    P =  12.46 years


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

                         (C) Copyright 2019 CBAT
2019 January 17                  (CBET 4602)              Daniel W. E. Green



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