[Iaude] CBET 4966: COMET C/2017 K2 (PANSTARRS)

quai at eps.harvard.edu quai at eps.harvard.edu
Wed May 12 08:32:11 EDT 2021


                                                  Electronic Telegram No. 4966
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/2017 K2 (PANSTARRS)
     Selected CCD total-magnitude and coma-diameter measurements for this
comet (cf. CBET 4393):  2017 June 16.96 UT, 18.5, 0'.2 (K. Yoshimoto, Yamaguchi,
Japan, remotely using a 0.43-m reflector at Nerpio, Spain); Sept. 30.50, 18.3,
-- (K. Kadota, Ageo, Japan, 0.25-m reflector); 2018 Jan. 12.82, 18.1, --
(Kadota); Apr. 18.73, 18.0, 0'.4 (Yoshimoto, Yamaguchi, 0.20-m reflector);
Aug. 17.54, 17.6, -- (Kadota); 2019 Feb. 2.74, 17.3, -- (Kadota); May 5.63,
16.9, -- (Kadota); Sept. 25.44, 16.4, -- (Kadota); 2020 Jan. 18.81, 16.2, --
(Kadota); Mar. 21.73, 15.8, -- (Kadota); May 14.33, 15.9, 0'.6 (C. S. Morris,
Fillmore, CA, U.S.A., 41-cm reflector); June 10.33, 15.7, 0'.8 (Morris);
28.91, 14.6, 0'.42 (T. Scarmato, Calabria, Italy, 25-cm reflector + R_c
filter); Aug. 2.51, 15.1, -- (Kadota); 13.22, 15.5, 0'.8 (Morris); 16.83,
15.2, 0'.42 (Scarmato); Sept. 3.22, 15.5, 0'.9 (Morris); 23.18, 15.4, 1'.1
(Morris); Oct. 11.45, 15.2, 0'.8 (Yoshimoto); 17.14, 15.3, 1'.0 (Morris);
24.47, 14.8, -- (Kadota); Nov. 11.10, 15.1, 1'.0 (Morris); 17.11, 15.2, 1'.2
(Morris); Dec. 6.37, 14.5, -- (Kadota); 2021 Feb. 3.84, 14.3, -- (Kadota);
9.77, 13.7, 1'.7 (K. Harikae, Chiba, Japan, 0.15-m reflector + digital
camera); 21.74, 14.1, 1'.4 (Harikae); Mar. 10.74, 14.5, 0'.9 (Harikae); 18.44,
13.7, 1'.2 (H. Sato, Tokyo, Japan, remotely with a 0.43-m astrograph near
Mayhill, NM, USA); 25.77, 13.7, -- (Kadota); Apr. 8.90, 14.5, 0'.9 (Scarmato);
18.68, 14.0, 1'.2 (Yoshimoto); May 1.65, 13.3, -- (Kadota).
     Visual total-magnitude and coma-diameter estimates by W. Hasubick,
Buchloe, Germany, with a 44-cm reflector:  2020 July 12.90 UT, 14.5, 0'.3;
Sept. 12.91, 13.5, 0'.2.
     Pre-discovery observations of this comet were identified as far back as
2013 May 12.6 UT at Mauna Kea, when the total magnitude was given as 21.4-22.1
(cf. MPC 105642).  Selected pre-discovery Catalina Sky Survey magnitudes are
as follows (op.cit.):  2015 Nov. 23.1, 19.8; 2016 May 6.5, 19.9; July 11.3,
19.7; 2017 Mar. 22.5, 19.1; Apr. 7.5, 18.8; 16.5, 19.2; 26.4, 19.6; May 3.4,
19.5.
     The following updated orbital elements by S. Nakano (CBAT) are from 4213
observations spanning 2013 May 12-2021 May 3 (mean residual 0".4); the
corresponding original and future values of 1/a are +0.000028 and +0.001121,
respectively.  These elements indicate that the comet will pass 2.66 AU from
Jupiter on 2024 Oct. 15 and 7.88 AU from Uranus on 2029 Oct. 16 UT.

                    Epoch = 2022 Dec.  7.0 TT
     T = 2022 Dec. 19.67178 TT        Peri. = 236.19715
     e = 1.0008506                    Node  =  88.23537 2000.0
     q = 1.7969443 AU                 Incl. =  87.56309

The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 3.0 and 2.5n = 8 for the
magnitudes, which well represent the reported total magnitudes from 2013
to date.  This is intrinsically a fairly bright comet, with presumably a
relatively large nucleus.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2021 04 16    18 26.34   +40 45.8    6.420    6.606    96.3     8.7  13.6
2021 04 26    18 23.34   +41 37.2    6.267    6.526   100.5     8.7  13.5
2021 05 06    18 18.85   +42 23.0    6.120    6.444   104.3     8.7  13.4
2021 05 16    18 12.89   +43 00.0    5.983    6.363   107.7     8.7  13.3
2021 05 26    18 05.61   +43 24.8    5.856    6.281   110.3     8.7  13.2
2021 06 05    17 57.26   +43 34.5    5.743    6.199   112.2     8.7  13.1
2021 06 15    17 48.16   +43 26.6    5.645    6.116   113.2     8.8  13.0
2021 06 25    17 38.76   +42 59.4    5.561    6.033   113.1     8.9  13.0
2021 07 05    17 29.53   +42 12.4    5.494    5.950   112.0     9.1  12.9
2021 07 15    17 20.91   +41 06.3    5.443    5.866   109.8     9.4  12.8
2021 07 25    17 13.29   +39 42.8    5.407    5.782   106.7     9.7  12.8
2021 08 04    17 06.96   +38 04.5    5.386    5.698   102.9    10.0  12.7
2021 08 14    17 02.10   +36 14.5    5.377    5.614    98.3    10.3  12.6
2021 08 24    16 58.80   +34 16.3    5.378    5.529    93.3    10.5  12.6
2021 09 03    16 57.03   +32 13.1    5.387    5.444    87.9    10.7  12.5
2021 09 13    16 56.75   +30 07.8    5.401    5.358    82.2    10.7  12.5
2021 09 23    16 57.86   +28 03.3    5.417    5.272    76.4    10.7  12.4
2021 10 03    17 00.24   +26 01.7    5.433    5.186    70.5    10.5  12.4
2021 10 13    17 03.76   +24 04.8    5.445    5.099    64.7    10.2  12.3
2021 10 23    17 08.29   +22 14.2    5.450    5.012    59.1     9.8  12.3
2021 11 02    17 13.69   +20 31.0    5.447    4.925    53.7     9.3  12.2
2021 11 12    17 19.85   +18 55.9    5.432    4.838    48.8     8.9  12.2
2021 11 22    17 26.63   +17 29.6    5.404    4.750    44.5     8.4  12.1
2021 12 02    17 33.91   +16 12.5    5.361    4.661    41.0     8.0  12.0
2021 12 12    17 41.57   +15 04.7    5.300    4.573    38.6     7.7  11.9
2021 12 22    17 49.50   +14 06.3    5.223    4.484    37.6     7.7  11.8
2022 01 01    17 57.57   +13 17.3    5.127    4.395    38.1     7.9  11.7
2022 01 11    18 05.67   +12 37.4    5.012    4.306    40.0     8.4  11.6
2022 01 21    18 13.67   +12 06.3    4.879    4.216    43.2     9.2  11.4
2022 01 31    18 21.43   +11 43.6    4.727    4.126    47.5    10.1  11.3
2022 02 10    18 28.81   +11 28.6    4.559    4.036    52.6    11.2  11.1
2022 02 20    18 35.67   +11 20.7    4.374    3.945    58.3    12.3  11.0
2022 03 02    18 41.83   +11 18.8    4.176    3.855    64.5    13.4  10.8
2022 03 12    18 47.10   +11 21.9    3.965    3.764    71.2    14.5  10.6
2022 03 22    18 51.26   +11 28.5    3.744    3.674    78.3    15.4  10.4
2022 04 01    18 54.06   +11 36.8    3.515    3.583    85.8    16.1  10.2
2022 04 11    18 55.19   +11 44.2    3.283    3.492    93.6    16.6   9.9
2022 04 21    18 54.34   +11 47.7    3.050    3.401   101.8    16.8   9.7
2022 05 01    18 51.11   +11 43.0    2.821    3.311   110.5    16.6   9.4
2022 05 11    18 45.09   +11 24.7    2.601    3.220   119.5    15.8   9.1
2022 05 21    18 35.94   +10 45.8    2.395    3.130   128.8    14.6   8.9
2022 05 31    18 23.39   +09 38.3    2.210    3.041   138.0    12.9   8.6
2022 06 10    18 07.50   +07 53.8    2.054    2.952   146.2    11.0   8.3
2022 06 20    17 48.77   +05 26.4    1.932    2.864   151.1     9.9   8.1
2022 06 30    17 28.19   +02 15.8    1.850    2.776   149.9    10.6   7.9
2022 07 10    17 07.24   -01 30.8    1.811    2.690   142.5    13.3   7.7
2022 07 20    16 47.50   -05 39.5    1.815    2.605   131.9    16.9   7.6
2022 07 30    16 30.24   -09 54.6    1.855    2.522   120.2    20.4   7.6
2022 08 09    16 16.28   -14 04.1    1.923    2.441   108.4    23.2   7.5
2022 08 19    16 05.91   -18 01.2    2.011    2.362    97.2    25.2   7.5
2022 08 29    15 59.05   -21 44.4    2.109    2.286    86.8    26.2   7.5
2022 09 08    15 55.46   -25 15.1    2.210    2.214    77.0    26.3   7.5
2022 09 18    15 54.82   -28 36.2    2.307    2.145    68.0    25.8   7.5
2022 09 28    15 56.82   -31 50.8    2.395    2.080    59.8    24.6   7.4
2022 10 08    16 01.26   -35 02.3    2.470    2.020    52.3    23.0   7.4
2022 10 18    16 07.97   -38 13.5    2.529    1.966    45.6    21.2   7.4
2022 10 28    16 16.96   -41 27.2    2.570    1.919    40.0    19.5   7.3
2022 11 07    16 28.34   -44 45.8    2.592    1.878    35.7    17.9   7.3
2022 11 17    16 42.40   -48 11.4    2.594    1.845    33.0    17.0   7.2
2022 11 27    16 59.76   -51 45.7    2.577    1.820    32.2    16.8   7.1
2022 12 07    17 21.40   -55 29.1    2.544    1.804    33.4    17.5   7.1
2022 12 17    17 49.05   -59 19.9    2.497    1.797    36.1    18.8   7.0
2022 12 27    18 25.62   -63 12.0    2.440    1.799    39.9    20.5   7.0
2023 01 06    19 15.63   -66 49.6    2.380    1.811    44.3    22.3   6.9
2023 01 16    20 24.64   -69 39.8    2.321    1.831    48.9    23.9   6.9
2023 01 26    21 53.28   -70 48.7    2.271    1.859    53.3    25.1   6.9
2023 02 05    23 27.26   -69 28.7    2.238    1.896    57.3    25.9   7.0
2023 02 15    00 46.89   -65 44.4    2.227    1.940    60.4    26.3   7.0
2023 02 25    01 46.52   -60 24.8    2.243    1.991    62.5    26.2   7.1
2023 03 07    02 30.62   -54 20.3    2.288    2.047    63.5    25.7   7.3
2023 03 17    03 04.49   -48 07.1    2.362    2.109    63.2    24.9   7.5
2023 03 27    03 31.80   -42 08.8    2.461    2.176    61.8    23.8   7.7
2023 04 06    03 54.76   -36 39.0    2.582    2.247    59.5    22.6   7.9
2023 04 16    04 14.73   -31 44.3    2.718    2.321    56.6    21.1   8.1
2023 04 26    04 32.56   -27 26.2    2.863    2.398    53.1    19.6   8.3
2023 05 06    04 48.76   -23 43.8    3.012    2.478    49.5    18.0   8.5


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

                         (C) Copyright 2021 CBAT
2021 May 12                      (CBET 4966)              Daniel W. E. Green



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