[Iaude] CBET 4805: COMET 12P

quai at eps.harvard.edu quai at eps.harvard.edu
Sat Jun 27 21:38:08 EDT 2020


                                                  Electronic Telegram No. 4805
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 12P/PONS-BROOKS
     This comet (cf. CBET 4727) has been recovered on G-band CCD images taken
on June 10 and 17 (astrometry tabulated below) with the Lowell Observatory
4.3-m Discovery Telescope (+ Large Monolithic Imager) by M. M. Knight, C. E.
Holt, Q.-Z. Ye, L. M. Feaga, M. S. P. Kelley, L. Shumar, J. Sanborn, and A.
Hayslip (and measured by Ye and T. L. Farnham).  Ye adds that the head of the
comet had a full-width-at-half-maximum (FWHM) size of about 1".2, which was
largely consistent with the sizes of nearby stars; on a stacked image, there
is a broad tail about 3" long pointing towards p.a. about 170-200 degrees,
implying that the comet has been active for some time (now at r = 11.9 AU).

     2020 UT             R.A. (2000) Decl.       Mag.   Observer
     June 10.39794   18 04 12.24   +20 53 53.1   22.8   Knight
          10.40191   18 04 12.14   +20 53 53.1   22.7     "
          10.44291   18 04 11.21   +20 53 55.9   23.2     "
          17.31258   18 01 46.05   +21 01 28.6   24.0     "
          17.31624   18 01 45.96   +21 01 28.8   24.0     "
          17.31990   18 01 45.88   +21 01 29.0   23.8     "
          17.32354   18 01 45.80   +21 01 29.3   23.9     "
          17.32720   18 01 45.72   +21 01 29.4   23.8     "

     Regarding the linked orbit by T. Kobayashi on CBET 4727, the residuals
for the 2020 observations are off by about -2" in R.A. and about -5" in Decl.,
with the indicated correction being Delta(T) = +0.16 day.  S. Nakano, Sumoto,
Japan, reports the following linked orbital elements from 1074 observations
spanning 1812 July 21-2020 June 17 and four apparitions (weighted mean
residual 1".35); see CBET 4727 for details on the 19th-century astrometry.
The associated non-gravitational parameters are A_1 = +0.06 and A_2 = -0.0270.
The comet passed 3.71 AU from Uranus on 1819 Apr. 26 and 1.62 AU from Saturn
on 1957 July 29 UT.  This orbit gives T = 1385 Nov. 6.25 and 1457 Jan. 30.06
TT, with residuals of a couple degrees for C/1385 U1 and about a degree for
C/1457 A1.

                    Epoch = 1812 Aug. 30.0 TT
     T = 1812 Sept.15.82498 TT        Peri. = 199.28730
     e = 0.9553351                    Node  = 255.63886 2000.0
     q = 0.7771150 AU                 Incl. =  73.95648
       a = 17.3988017 AU   n = 0.01358079   P =  72.57 years

                    Epoch = 1884 Jan. 25.0 TT
     T = 1884 Jan. 26.21585 TT        Peri. = 199.17512
     e = 0.9550459                    Node  = 255.77461 2000.0
     q = 0.7757414 AU                 Incl. =  74.04054
       a = 17.2563096 AU   n = 0.01374935   P =  71.68 years

                    Epoch = 1954 May  18.0 TT
     T = 1954 May  22.87787 TT        Peri. = 199.02671
     e = 0.9548407                    Node  = 255.89104 2000.0
     q = 0.7736655 AU                 Incl. =  74.17695
       a = 17.1319179 AU   n = 0.01389937   P =  70.91 years

                    Epoch = 2024 May  10.0 TT
     T = 2024 Apr. 21.00504 TT        Peri. = 198.98782
     e = 0.9545989                    Node  = 255.85602 2000.0
     q = 0.7807733 AU                 Incl. =  74.19143
       a = 17.1972223 AU   n = 0.01382027   P =  71.32 years

                    Epoch = 2095 Aug. 26.0 TT
     T = 2095 Aug. 10.86168 TT        Peri. = 198.89121
     e = 0.9548999                    Node  = 255.92846 2000.0
     q = 0.7836207 AU                 Incl. =  74.04352
       a = 17.3751293 AU   n = 0.01360855   P =  72.43 years

The following ephemeris by the undersigned from the above elements uses
power-law photometric parameters H = 4.0 and 2.5n = 12 for the total
magnitudes.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2020 05 31    18 07.69   +20 37.0   11.290   11.987   131.5     3.6  22.2
2020 07 10    17 53.70   +21 04.9   11.065   11.770   132.1     3.7  22.1
2020 08 19    17 42.81   +19 59.4   11.163   11.551   110.1     4.7  22.0
2020 09 28    17 40.62   +18 06.6   11.430   11.328    81.6     5.0  21.9
2020 11 07    17 47.72   +16 29.6   11.643   11.102    54.9     4.2  21.9
2020 12 17    18 01.02   +15 55.5   11.613   10.873    39.6     3.3  21.8
2021 01 26    18 15.64   +16 47.1   11.259   10.640    49.1     4.0  21.6
2021 03 07    18 26.19   +19 01.1   10.636   10.404    73.9     5.3  21.3
2021 04 16    18 27.76   +22 03.6    9.913   10.164   101.7     5.5  21.1
2021 05 26    18 18.08   +24 46.3    9.308    9.920   124.7     4.8  20.8
2021 07 05    18 00.88   +25 48.9    8.993    9.672   129.6     4.6  20.6
2021 08 14    17 45.81   +24 42.1    8.994    9.420   112.0     5.7  20.5
2021 09 23    17 41.21   +22 19.7    9.183    9.163    85.7     6.3  20.4
2021 11 02    17 48.68   +20 07.2    9.352    8.902    60.3     5.6  20.2
2021 12 12    18 04.78   +19 10.3    9.318    8.635    43.9     4.5  20.1
2022 01 21    18 23.98   +20 03.5    8.991    8.364    47.9     5.0  19.8
2022 03 02    18 39.94   +22 52.1    8.402    8.087    68.2     6.5  19.5
2022 04 11    18 46.04   +27 07.3    7.685    7.803    93.1     7.4  19.1
2022 05 21    18 36.93   +31 29.8    7.035    7.514   114.7     7.0  18.7
2022 06 30    18 13.92   +33 53.7    6.618    7.218   122.7     6.8  18.4
2022 08 09    17 50.09   +32 56.5    6.487    6.915   110.9     7.9  18.1
2022 09 18    17 40.46   +29 38.8    6.546    6.604    88.9     8.8  17.9
2022 10 28    17 48.98   +26 16.0    6.615    6.284    66.5     8.3  17.7
2022 12 07    18 11.31   +24 33.6    6.530    5.956    50.8     7.4  17.4
2023 01 16    18 40.84   +25 30.3    6.208    5.618    49.4     7.6  17.0
2023 02 25    19 10.55   +29 32.7    5.663    5.268    61.8     9.5  16.4
2023 04 06    19 32.17   +36 37.9    4.991    4.907    79.4    11.6  15.8
2023 05 16    19 33.78   +45 46.5    4.332    4.532    94.9    12.8  15.1
2023 06 25    18 59.14   +53 48.5    3.807    4.142   102.1    13.9  14.3
2023 08 04    17 55.68   +55 27.3    3.456    3.734    97.9    15.6  13.6
2023 09 13    17 19.54   +50 07.5    3.211    3.306    86.5    17.7  12.8
2023 10 23    17 33.16   +43 09.5    2.952    2.854    74.6    19.6  11.8
2023 12 02    18 27.92   +38 36.4    2.591    2.376    66.4    22.4  10.6
2024 01 11    20 06.46   +37 53.2    2.143    1.868    60.6    27.3   8.9
2024 02 20    22 48.66   +37 21.1    1.751    1.339    49.5    34.1   6.7
2024 03 31    02 05.10   +23 33.5    1.611    0.875    28.6    33.1   4.3
2024 05 10    04 31.52   -03 41.0    1.578    0.859    29.6    35.5   4.2
2024 06 19    07 00.36   -29 54.8    1.578    1.313    55.9    39.9   6.4
2024 07 29    10 07.56   -44 45.6    1.983    1.842    67.0    30.5   8.7
2024 09 07    12 40.00   -47 29.2    2.730    2.351    57.7    21.2  10.6
2024 10 17    14 23.45   -47 30.8    3.520    2.831    40.0    13.1  12.2
2024 11 26    15 39.65   -47 42.1    4.128    3.283    27.4     7.9  13.3
2025 01 05    16 36.60   -48 20.6    4.428    3.712    38.8     9.5  14.1


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

                         (C) Copyright 2020 CBAT
2020 June 28                     (CBET 4805)              Daniel W. E. Green



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