[Iaude] CBET 4830: COMET C/2020 P3

[quai at eps.harvard.edu]

                                                  Electronic Telegram No. 4830
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/2020 P3 (ATLAS)
     An apparently asteroidal object discovered on CCD images taken on Aug.
9.6 UT with a 0.5-m f/2 Schmidt reflector at Mauna Loa, Hawaii, in the course
of the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) search program
has been found to show cometary appearance by CCD astrometrists elsewhere
after it was posted on the Minor Planet Center's PCCP webpage.  The discovery
observations are tabulated below,

     2020 UT             R.A. (2000) Decl.       Mag.
     Aug.  9.56992    3 45 36.80   +70 55 54.8   19.0
           9.57361    3 45 37.10   +70 55 57.1   18.8
           9.58374    3 45 37.44   +70 56 04.1   18.9
           9.59020    3 45 37.91   +70 56 07.0   19.1

On Aug. 12, after observers elsewhere were reporting cometary activity to
the Central Bureau and to the MPC, A. Fitzsimmons (Queen's University,
Belfast) reported that the object had been reported on the discovery images
as "possibly cometary" by J. Robinson, but this information was withheld
until follow-up observations were obtained on Aug. 10.6 UT by J. D. Armstrong,
E. J. Guarin, and J. O. Teagarden with the 2.0-m "Faulkes Telescope North",
relating that four 120-s VR-filter images show a coma with size 2".0 (full-
width-at-half-maximum, in 1".3 seeing) with a 15" tail in p.a. 230 degrees.
     E. Guido, Castellammare di Stabia, Italy, writes that sixty-six stacked
90-s unfiltered exposures obtained remotely with a 0.5-m f/8 Ritchey-Chretien
reflector at the Osservatorio Salvatore di Giacomo, Agerola, by A. Catapano
and himself on Aug. 10.03-10.09 UT show a compact coma of mag 19.3-19.4 and
about 8" in diameter with a tail 10" long in p.a. 230 degrees; forty-six
additional stacked 90-s exposures taken around Apr. 11.07 again show a
compact coma about 8" in diameter and a 10" tail in p.a. 235 deg.  Guido and
Catapano stacked sixty-six additional 90-s exposures taken on Aug. 12.04-
12.09 that again show a compact coma about 8" in diameter and a tail 10"
long in p.a. 230 deg.  Twenty-four stacked 60-s exposures taken remotely by
H. Sato, Tokyo, Japan, with a 0.43-m f/6.8 astrograph located near Mayhill,
NM, USA, on Aug. 10.4 show a strongly condensed coma 8" in diameter with no
tail; the magnitude was 18.8 as measured within a circular aperture of
radius 5".7.  E. Bryssinck, Kruibeke, Belgium, writes that twenty stacked
60-s exposures were taken remotely by a large team of observers with a
"Telescope Live" 0.7-m f/8 reflector operated by M. Rochetto at Oria,
Almeria, Spain, on Aug. 13.14-13.16, which show the object to be definitely
a comet with a condensed 8" coma and a tail 17" long in p.a. about 230
degrees; the magnitude was measured as 18.8 in an aperture of radius 5".
Forty-five stacked 60-s exposures taken on Aug. 15.1 by L. Buzzi, Varese,
Italy, with a 0.84-m f/3.5 reflector (and measured by A. Aletti) show a
compact coma 5" wide and a short, straight tail 15" long in p.a. 235 degrees.
     The available astrometry appear on MPEC 2020-Q01.  The following 
preliminary parabolic orbital elements by S. Nakano, Central Bureau, are 
from 82 observations spanning Aug. 9-15 (mean residual 0".3).

     T = 2021 Mar.  9.5743 TT         Peri. =  78.9244
                                      Node  =  19.3560  2000.0
     q = 6.881259 AU                  Incl. =  61.8171

The following ephemeris by the undersigned from the above elements 
uses photometric power-law parameters H = 8.0 and 2.5n = 8 for the 
magnitudes.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2020 07 10    03 15.83   +66 08.8    7.549    7.062    58.0     7.0  19.2
2020 07 15    03 21.00   +66 54.2    7.504    7.055    60.3     7.2  19.2
2020 07 20    03 26.10   +67 40.3    7.457    7.048    62.6     7.4  19.1
2020 07 25    03 31.08   +68 27.0    7.408    7.041    65.1     7.5  19.1
2020 07 30    03 35.93   +69 14.3    7.358    7.034    67.6     7.7  19.1
2020 08 04    03 40.62   +70 02.1    7.307    7.027    70.1     7.8  19.1
2020 08 09    03 45.11   +70 50.4    7.256    7.021    72.7     7.9  19.1
2020 08 14    03 49.37   +71 39.0    7.203    7.014    75.3     8.0  19.1
2020 08 19    03 53.33   +72 28.0    7.151    7.008    77.9     8.1  19.0
2020 08 24    03 56.94   +73 17.2    7.098    7.002    80.5     8.2  19.0
2020 08 29    04 00.12   +74 06.5    7.046    6.996    83.1     8.2  19.0
2020 09 03    04 02.81   +74 55.8    6.994    6.990    85.6     8.3  19.0
2020 09 08    04 04.91   +75 44.9    6.943    6.984    88.2     8.3  19.0
2020 09 13    04 06.30   +76 33.6    6.893    6.979    90.8     8.3  18.9
2020 09 18    04 06.83   +77 21.8    6.844    6.974    93.2     8.3  18.9
2020 09 23    04 06.34   +78 09.2    6.797    6.968    95.7     8.2  18.9
2020 09 28    04 04.63   +78 55.5    6.752    6.963    98.1     8.2  18.9
2020 10 03    04 01.50   +79 40.2    6.709    6.958   100.4     8.1  18.9
2020 10 08    03 56.67   +80 23.1    6.668    6.954   102.5     8.1  18.9
2020 10 13    03 49.87   +81 03.6    6.629    6.949   104.6     8.0  18.8
2020 10 18    03 40.81   +81 41.0    6.594    6.944   106.6     7.9  18.8
2020 10 23    03 29.24   +82 14.7    6.561    6.940   108.4     7.8  18.8
2020 10 28    03 15.06   +82 43.8    6.532    6.936   110.1     7.7  18.8
2020 11 02    02 58.32   +83 07.8    6.506    6.932   111.5     7.7  18.8
2020 11 07    02 39.39   +83 25.7    6.483    6.928   112.8     7.6  18.8