[Iaude] CBET 5306: COMET P/2023 RL_75 = P/2002 T6

[quai at eps.harvard.edu]

                                                  Electronic Telegram No. 5306
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/2023 RL_75 = P/2002 T6 (NEAT-LINEAR)
     M. Rudenko, Minor Planet Center, reports that an apparently asteroidal
object found by E. Schwab on CCD images obtained on Sept. 9 UT with the 0.8-m
f/3 Schmidt telescope at Calar Alto (astrometry tabulated below), and given
the minor-planet designation 2023 RL_75 by the MPC, has been identifed with
comet P/2002 T6 (cf. IAUC 8002).

     2023 UT             R.A. (2000) Decl.       Mag.   Observer
     Sept. 9.09250    1 01 53.60   +10 40 13.5   21.7   Schwab
           9.11089    1 01 53.27   +10 40 10.1   21.4     "
           9.12929    1 01 52.96   +10 40 06.9   21.2     "

The available astrometry appears on MPEC 2023-U279 and includes CCD astrometry
(without comment) from Sept. 5.1-5.2 UT obtained by J. Maikner with a 0.30-m
telescope (with the magnitude then given as 20.4-20.5).  H. Sato (Bunkyo-ku,
Tokyo, Japan) informs the Central Bureau that a post on an online discussion
group suggesting the identification led him to observe the comet on Oct. 25.2,
in which eleven stacked 120-s CCD exposures taken with a "Deep Sky Chile"
0.51-m f/6.8 astrograph at Rio Hurtado, Chile, shows a moderately condensed
coma 4" in diameter with no tail; the magnitude was 19.3 as measured within a
circular aperture of radius 2".2.
     The residuals for the recovery observations above are +0.12 deg in R.A.
and +0.03 deg in Decl. from the prediction in NK 1066 and in the ICQ's 2021
Comet Handbook, with a corresponding correction of Delta(T) = -0.64 day.  The
following linked orbital elements by S. Nakano (Central Bureau) are from 431
observations spanning 2002-2023 (mean residual 0".7).  Nakano states that
the identification 2023 RL_75 = P/2002 T6 was made by Hidetaka Sato.  The
comet passed 1.67 AU from Saturn on 2018 Apr. 30 and will pass 1.67 AU from
Jupiter on 2024 May 22 UT (coincidentally the same distances); also, the comet
passed 1.59 AU from Jupiter in 1919 May and 0.89 AU from Saturn in 1924 Oct.

                    Epoch = 2003 June 10.0 TT
     T = 2003 June 27.01545 TT        Peri. = 217.57304
     e = 0.5573311                    Node  = 209.04572 2000.0
     q = 3.3870835 AU                 Incl. =  11.00925
       a =  7.6515059 AU   n = 0.04656758   P =  21.16 years

                    Epoch = 2024 July 29.0 TT
     T = 2024 July 15.54787 TT        Peri. = 218.95141
     e = 0.5671066                    Node  = 205.99605 2000.0
     q = 3.3895578 AU                 Incl. =  10.83576
       a =  7.8300052 AU   n = 0.04498430   P =  21.91 years

                    Epoch = 2045 Oct. 27.0 TT
     T = 2045 Oct.  7.17193 TT        Peri. = 218.14789
     e = 0.5614668                    Node  = 205.57049 2000.0
     q = 3.3764599 AU                 Incl. =  10.87077
       a =  7.6994387 AU   n = 0.04613340   P =  21.36 years

The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 12.5 and 2.5n = 8 for the
magnitudes.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2023 10 23    00 43.41   +07 11.4    2.893    3.858   163.6     4.2  19.5
2023 10 28    00 41.37   +06 45.1    2.902    3.842   158.1     5.5  19.5
2023 11 02    00 39.56   +06 20.0    2.918    3.826   152.5     6.9  19.5
2023 11 07    00 38.03   +05 56.5    2.941    3.811   147.0     8.1  19.5
2023 11 12    00 36.81   +05 35.0    2.970    3.796   141.6     9.3  19.5
2023 11 17    00 35.96   +05 15.9    3.004    3.781   136.3    10.4  19.5
2023 11 22    00 35.48   +04 59.4    3.043    3.766   131.0    11.4  19.5
2023 11 27    00 35.41   +04 45.7    3.087    3.752   125.9    12.3  19.5
2023 12 02    00 35.75   +04 35.0    3.135    3.737   120.8    13.1  19.6
2023 12 07    00 36.50   +04 27.2    3.186    3.723   115.9    13.8  19.6
2023 12 12    00 37.67   +04 22.5    3.240    3.709   111.0    14.3  19.6
2023 12 17    00 39.25   +04 20.7    3.297    3.696   106.3    14.8  19.6
2023 12 22    00 41.22   +04 21.9    3.355    3.682   101.7    15.2  19.7
2023 12 27    00 43.59   +04 26.0    3.415    3.669    97.1    15.4  19.7
2024 01 01    00 46.32   +04 32.7    3.475    3.656    92.7    15.6  19.7
2024 01 06    00 49.41   +04 42.0    3.536    3.644    88.4    15.7  19.7
2024 01 11    00 52.84   +04 53.7    3.597    3.631    84.2    15.6  19.8
2024 01 16    00 56.59   +05 07.6    3.658    3.619    80.0    15.5  19.8
2024 01 21    01 00.65   +05 23.7    3.718    3.607    76.0    15.3  19.8
2024 01 26    01 04.98   +05 41.6    3.776    3.596    72.0    15.1  19.8
2024 01 31    01 09.59   +06 01.2    3.834    3.584    68.1    14.8  19.9
2024 02 05    01 14.45   +06 22.4    3.889    3.573    64.3    14.4  19.9
2024 02 10    01 19.55   +06 45.0    3.943    3.563    60.5    14.0  19.9
2024 02 15    01 24.87   +07 08.8    3.995    3.552    56.8    13.5  19.9
2024 02 20    01 30.40   +07 33.6    4.044    3.542    53.2    12.9  19.9


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

                         (C) Copyright 2023 CBAT
2023 October 30                  (CBET 5306)              Daniel W. E. Green