[Iaude] CBET 4836: COMET C/2020 Q1

quai at eps.harvard.edu quai at eps.harvard.edu
Wed Aug 19 22:10:08 EDT 2020


                                                  Electronic Telegram No. 4836
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 Q1 (BORISOV)
     Gennady Borisov reports his discovery of a new comet with a diffuse coma
of size about 25" and no tail on CCD images obtained on Aug. 17.96-17.98 UT
with a 0.65-m f/1.5 astrograph located at the MARGO observatory near Nauchnij,
Crimea.  The comet's total red magnitude was 17.5 as measured in a circular
aperture of size 0'.5.  Borisov's discovery observations are tabulated below.

     2020 UT             R.A. (2000) Decl.       Mag.   Observer
     Aug. 17.96858    5 35 05.20   +30 15 47.1   17.8   Borisov
          17.97627    5 35 04.95   +30 16 00.6   17.6     "
          17.98376    5 35 04.55   +30 16 17.3   17.6     "

After the comet was posted on the Minor Planet Center's PCCP webpage, numerous
other CCD astrometrists have commented on the cometary appearance.  Eight
stacked 60-s exposures taken on Aug. 18.8 UT by K. Yoshimoto, Yamaguchi,
Japan, with a 0.20-m f/8 Ritchey-Chretien reflector show a coma of diameter
0'.4 and total mag 16.3 with no tail.  E. Guido, Castellammare di Stabia,
Italy, writes that 144 stacked unfiltered 30-s exposures obtained remotely
by A. Catapano and himself on Aug. 19.06-19.10 with a 0.5-m f/8 Ritchey-
Chretien reflector located at the Osservatorio Salvatore di Giacomo, Agerola,
show a very diffuse coma about 1' in diameter of magnitude 17.4-17.6, with
a brighter inner coma of size about 30".  Thirty additional stacked 50-s
unfiltered exposures taken remotely by A. Valvasori and Guido on Aug. 19.09-
19.11 with an iTelescope 0.32-m f/8 reflector at Nerpio, Spain, show a very
diffuse coma about 1' in diameter (mag 16.9-17.2).  Forty stacked 90-s
unfiltered exposures taken by E. Bryssinck, Kruibeke, Belgium, with a 0.4-m
f/3.8 reflector show a diffuse central condensation with a circular, very
faint coma of size about 48" and no tail visible on Aug. 19.07-19.12; the
magnitude was 17.9 as measured in an aperture of radius 5".  Unfiltered
exposures taken on Aug. 19.09-19.11 by F. Kugel with a 0.4-m f/2.8 reflector
at the Observatoire Chante-Perdrix, Dauban, France, show a coma of size about
2' with no obvious tail (but there is a possible short tail toward p.a. around
260 degrees); the total magnitude was 15.9 as measured in a 0'.4 aperture
radius, and the magnitude was 17.9-18.0 in a 5".8 aperture radius.  K. Kadota,
Ageo, Japan, reports that images taken on Aug. 19.7 with a 0.25-m f/5
reflector show a diffuse, faint coma of diameter 0'.8 and total magnitude
15.8, with a central condensation but no tail.
     The available astrometry appear on MPEC 2020-Q109.  The following
preliminary parabolic orbital elements by S. Nakano (CBAT) are from 39
spanning observations Aug. 17-19 (mean residual 0".7).

     T = 2020 Aug. 14.9954 TT         Peri. =  10.1491
                                      Node  =  52.5698  2000.0
     q = 1.321751 AU                  Incl. = 142.7075

The following ephemeris by the undersigned from the above orbital elements use
photometric power-law parameters H = 14.0 and 2.5n = 8 for the magnitudes.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2020 07 30    05 42.36   +21 31.9    1.930    1.343    41.2    29.8  16.5
2020 08 04    05 41.46   +23 25.0    1.818    1.332    46.1    33.3  16.3
2020 08 09    05 39.97   +25 33.2    1.700    1.325    51.1    36.6  16.1
2020 08 14    05 37.69   +28 00.9    1.577    1.322    56.5    39.7  16.0
2020 08 19    05 34.26   +30 53.9    1.450    1.323    62.0    42.5  15.8
2020 08 24    05 29.14   +34 20.1    1.322    1.329    67.9    44.9  15.6
2020 08 29    05 21.40   +38 29.4    1.194    1.338    74.3    46.6  15.4
2020 09 03    05 09.33   +43 34.1    1.070    1.352    81.1    47.5  15.2
2020 09 08    04 49.51   +49 45.4    0.956    1.369    88.4    47.3  15.0
2020 09 13    04 14.33   +57 01.7    0.857    1.391    96.2    46.0  14.8
2020 09 18    03 06.24   +64 27.5    0.783    1.415   104.0    43.5  14.7
2020 09 23    01 01.19   +68 38.9    0.742    1.443   110.6    40.6  14.6
2020 09 28    22 42.95   +65 15.5    0.743    1.474   114.5    38.2  14.7
2020 10 03    21 20.69   +56 44.9    0.785    1.507   114.6    37.1  14.9
2020 10 08    20 39.01   +47 36.4    0.863    1.543   111.7    37.0  15.2
2020 10 13    20 16.51   +39 38.9    0.968    1.581   107.1    37.1  15.5
2020 10 18    20 03.52   +33 11.8    1.091    1.622   101.8    37.0  15.9
2020 10 23    19 55.76   +28 04.7    1.226    1.663    96.4    36.5  16.2
2020 10 28    19 51.16   +24 01.6    1.369    1.707    91.1    35.6  16.5
2020 11 02    19 48.57   +20 47.8    1.515    1.752    86.0    34.4  16.8
2020 11 07    19 47.38   +18 11.9    1.662    1.798    81.1    33.0  17.1


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

                         (C) Copyright 2020 CBAT
2020 August 20                   (CBET 4836)              Daniel W. E. Green



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