[Iaude] CBET 4707: COMET P/2019 W1

quai at eps.harvard.edu quai at eps.harvard.edu
Fri Dec 20 23:40:27 EST 2019


                                                  Electronic Telegram No. 4707
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 W1 (PANSTARRS)
     R. Weryk, Institute for Astronomy, University of Hawaii, reports the
discovery of another comet in images obtained in poor seeing (about 1".8) on
Nov. 29 UT with the Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala
(discovery observations tabulated below).  The comet was described as very
diffuse with a diameter of 2".5 and as having a broad tail 12" long in p.a.
260 degrees.

     2019 UT             R.A. (2000) Decl.       Mag.
     Nov. 29.54123    6 36 55.60   +48 33 37.9   20.5
          29.55366    6 36 55.06   +48 33 43.7   20.0
          29.56608    6 36 54.56   +48 33 49.4   20.2
          29.57854    6 36 53.96   +48 33 54.7   20.3

Weryk reports that follow-up CCD images were obtained in 1".0 seeing by R.
Wainscoat, H. Januszewski, A. Petric and himself with the 3.6-m Canada-
France-Hawaii Telescope on Mauna Kea on Dec. 3.6 UT that confirm the object
to be a diffuse comet with a coma diameter of 1".7 and a broad, 12"-long tail
in p.a. 220 and 290 degrees.  Weryk also provides pre-discovery astrometry
from very faint images of the comet that he identified from exposures taken
on 2018 Aug. 8 and 21 and on 2019 Jan. 1 and 24 with the Pan-STARRS1 1.8-m
Ritchey-Chretien reflector at Haleakala, for which he measured magnitudes
22-24, adding that the images were too faint to be able to comment on the
comet's morphology.
     After the object was posted on the Minor Planet Center's PCCP webpage,
other CCD astrometrists also reported on the cometary appearance.  K.
Sarneczky, Konkoly Observatory, reports that three stacked 120-s unfiltered
CCD images taken with the 0.60-m Schmidt telescope at Piszkesteto, Hungary,
on Nov. 30.9 UT show a condensed coma 6" in diameter and a straight tail
about 8" long in p.a. 260 deg.  R. Haver, Frasso Sabino, Italy, writes that
forty 90-s exposures taken on Dec. 1.0 with a 0.37-m f/7 Cassegrain reflector
show the comet's size to be about 1".7 larger than that of neighboring stars
(seeing 3".7).  P. Birtwhistle, Great Shefford, Berkshire, England, finds
an "only moderately concentrated" coma of diameter 10" and magnitude
19.3-19.5 with a 20" tail in p.a. 250 deg, adding that the object is
"obviously cometary" in images taken with a 0.41-m f/6.3 Schmidt-Cassegrain
reflector on Dec. 2.04-2.07.  Twelve stacked 120-s unfiltered images taken
by G. Favero and R. Furgoni with a 0.80-m f/4 reflector at the Osservatorio
del Celado, Castello Tesino, Italy, on Dec. 4.9 show an elongated coma and
a faint tail about 10" long in p.a. 240 deg.  Twenty stacked 60-s exposures
taken remotely by H. Sato, Tokyo, Japan, with a 0.43-m f/6.8 astrograph near
Mayhill, NM, USA, on Dec. 18.2 show a weakly condensed coma 10" in diameter
with no tail; he measured mag 21.3 within a circular aperture of radius 5".7.
G. Hug, Scranton, KS, U.S.A., reports that images taken on Dec. 18.35-18.39
with a 0.56-m reflector show little central condensation, the comet appearing
"nebulous" with a faint extension extending about 25" in p.a. about 220 deg;
he gave the magnitude as 20.9-21.0.
     The available astrometry appear on MPEC 2019-Y37.  The following
elliptical orbital elements by S. Nakano (Sumoto, Japan) are from 71
observations spanning 2018 Aug. 8-2019 Dec. 20 (mean residual 0".54); he
notes that a search of past archival astrometry found no other observations
of this comet.

                    Epoch = 2019 Apr. 27.0 TT
     T = 2019 May   8.09212 TT        Peri. =  18.76387
     e = 0.2659157                    Node  =  35.42842 2000.0
     q = 3.3399177 AU                 Incl. =  23.46359
       a =  4.5497739 AU   n = 0.10155922   P =   9.70 years

The following ephemeris by the undersigned uses photometric power-law
parameters H = 12.0 and 2.5n = 10, which only represent the post-perihelion
magnitudes (which make the comet 2-3 magnitudes brighter than the pre-
discovery, pre-perihelion magnitudes reported by Weryk above).

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2019 10 04    06 30.81   +40 54.2    3.199    3.416    93.9    17.0  19.9
2019 10 09    06 34.49   +41 31.4    3.137    3.421    97.9    16.8  19.8
2019 10 14    06 37.68   +42 09.8    3.077    3.426   102.0    16.5  19.8
2019 10 19    06 40.34   +42 49.5    3.018    3.432   106.2    16.2  19.8
2019 10 24    06 42.41   +43 30.2    2.962    3.437   110.4    15.7  19.7
2019 10 29    06 43.87   +44 12.0    2.908    3.443   114.7    15.2  19.7
2019 11 03    06 44.65   +44 54.4    2.856    3.449   119.0    14.6  19.7
2019 11 08    06 44.75   +45 37.2    2.809    3.455   123.4    13.9  19.6
2019 11 13    06 44.14   +46 20.0    2.765    3.461   127.7    13.1  19.6
2019 11 18    06 42.79   +47 02.1    2.726    3.467   132.1    12.2  19.6
2019 11 23    06 40.72   +47 43.1    2.692    3.473   136.3    11.3  19.6
2019 11 28    06 37.93   +48 22.1    2.663    3.480   140.3    10.4  19.5
2019 12 03    06 34.47   +48 58.4    2.640    3.486   144.0     9.6  19.5
2019 12 08    06 30.41   +49 31.3    2.623    3.493   147.3     8.8  19.5
2019 12 13    06 25.86   +50 00.1    2.613    3.500   150.0     8.1  19.5
2019 12 18    06 20.92   +50 24.2    2.609    3.507   151.8     7.6  19.5
2019 12 23    06 15.73   +50 43.1    2.612    3.514   152.6     7.4  19.5
2019 12 28    06 10.45   +50 56.6    2.621    3.521   152.2     7.5  19.6
2020 01 02    06 05.24   +51 04.5    2.638    3.529   150.8     7.8  19.6
2020 01 07    06 00.27   +51 07.1    2.661    3.536   148.4     8.4  19.6
2020 01 12    05 55.67   +51 04.6    2.690    3.544   145.4     9.1  19.6
2020 01 17    05 51.56   +50 57.5    2.726    3.552   141.8     9.9  19.7
2020 01 22    05 48.05   +50 46.5    2.767    3.559   138.0    10.7  19.7
2020 01 27    05 45.21   +50 32.0    2.814    3.567   133.9    11.5  19.8
2020 02 01    05 43.10   +50 14.8    2.865    3.575   129.7    12.2  19.8
2020 02 06    05 41.74   +49 55.6    2.921    3.584   125.4    13.0  19.9
2020 02 11    05 41.14   +49 34.8    2.981    3.592   121.1    13.6  19.9
2020 02 16    05 41.26   +49 13.0    3.045    3.600   116.8    14.2  20.0
2020 02 21    05 42.11   +48 50.5    3.111    3.609   112.6    14.7  20.0
2020 02 26    05 43.64   +48 27.7    3.180    3.617   108.4    15.0  20.1
2020 03 02    05 45.82   +48 04.9    3.251    3.626   104.3    15.4  20.2
2020 03 07    05 48.61   +47 42.1    3.324    3.635   100.3    15.6  20.2
2020 03 12    05 51.95   +47 19.7    3.398    3.643    96.3    15.7  20.3


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

                         (C) Copyright 2019 CBAT
2019 December 21                 (CBET 4707)              Daniel W. E. Green



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