[Iaude] CBET 5419: COMET C/2024 M1

[quai at eps.harvard.edu]

                                                  Electronic Telegram No. 5419
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/2024 M1 (ATLAS)
     An apparently asteroidal object discovered on CCD images taken on June 29
UT with a 0.5-m f/2 Schmidt reflector at Rio Hurtado, Chile, in the course of
the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) search program has
been found to show cometary appearance by astrometrists elsewhere after it was
posted on the Minor Planet Center's PCCP webpage.  The discovery observations
are tabulated below:

     2024 UT             R.A. (2000) Decl.       Mag.
     June 29.42281    4 52 44.54   -39 09 57.6   17.8
          29.42694    4 52 45.05   -39 09 54.4   17.6
          29.43200    4 52 45.62   -39 09 50.9   17.9
          29.44441    4 52 47.00   -39 09 41.7   18.3

K. Yoshimoto (Yamaguchi, Japan) writes that twenty stacked 30-s CCD exposures
taken on July 8.4 UT with an iTelescope 0.51-m f/6.8 corrected Dall-Kirkham
telescope at the "Deep Sky Chile" observatory at Rio Hurtado show a very
condensed coma 8" in diameter (total mag 18.4) and a faint tail 6" long in
p.a. 240 deg.  A stacked CMOS image taken by T. Prystavski (Lviv, Ukraine)
with a "Deep Sky Chile" 0.25-m f/3.8 Newtonian reflector at Rio Hurtado on
July 18.4 shows a very condensed coma that is slightly elongated (total mag
18.0) with a possible tail 8".7 long in p.a. 272 degrees.
     S. Deen (Simi Valley, CA, USA) subsequently identified apparently stellar
images of this comet in publicly available DECam observations obtained with
the 4-m reflector at Cerro Tololo on 2022 May 10.4 UT (mag g = 23.0) and on
2023 June 6.3 (z = 20.9).  The available astrometry appears on MPEC 2024-O16.
     The following orbital elements by S. Nakano (Central Bureau) are from
120 observations spanning 2022 May 10-2024 July 19 (mean residual 0".3).
There are no close approaches to any major planets.

                    Epoch = 2024 Nov. 26.0 TT
     T = 2024 Nov. 20.02750 TT        Peri. = 345.59915
     e = 0.9431014                    Node  =  76.21523 2000.0
     q = 1.7033995 AU                 Incl. =  73.71017
       a = 29.9374812 AU   n = 0.00601702   P = 163.8 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.
2024 06 19    04 31.99   -41 25.2    2.753    2.541    67.4    21.7  17.9
2024 06 29    04 51.92   -39 15.3    2.674    2.457    66.7    22.3  17.8
2024 07 09    05 10.69   -37 14.4    2.595    2.375    66.2    23.1  17.6
2024 07 19    05 28.27   -35 23.4    2.513    2.295    66.0    23.9  17.4
2024 07 29    05 44.61   -33 42.1    2.425    2.218    66.1    24.7  17.2
2024 08 08    05 59.68   -32 10.3    2.330    2.143    66.8    25.8  17.0
2024 08 18    06 13.36   -30 46.8    2.226    2.072    68.0    26.9  16.8
2024 08 28    06 25.53   -29 29.7    2.112    2.006    70.0    28.3  16.5
2024 09 07    06 36.01   -28 16.4    1.986    1.944    72.8    29.7  16.3
2024 09 17    06 44.52   -27 02.9    1.848    1.887    76.5    31.2  16.0
2024 09 27    06 50.69   -25 43.6    1.699    1.837    81.2    32.6  15.8
2024 10 07    06 53.95   -24 10.2    1.540    1.793    87.1    33.8  15.5
2024 10 17    06 53.49   -22 09.3    1.374    1.758    94.4    34.4  15.1
2024 10 27    06 48.16   -19 20.2    1.204    1.731   103.5    33.9  14.8
2024 11 06    06 36.29   -15 09.5    1.039    1.713   115.0    31.6  14.5
2024 11 16    06 15.85   -08 48.3    0.892    1.704   129.8    26.5  14.1
2024 11 26    05 45.08   +00 31.6    0.783    1.705   148.6    17.5  13.8
2024 12 06    05 04.25   +12 30.3    0.737    1.716   169.5     6.0  13.7
2024 12 16    04 18.20   +24 33.5    0.771    1.735   162.5     9.8  13.9
2024 12 26    03 35.08   +33 54.6    0.878    1.764   142.8    19.7  14.2
2025 01 05    03 01.26   +40 08.7    1.033    1.801   126.6    26.0  14.6
2025 01 15    02 38.46   +44 16.3    1.216    1.846   113.7    29.2  15.1
2025 01 25    02 25.31   +47 15.1    1.412    1.897   103.2    30.3  15.5
2025 02 04    02 19.78   +49 40.1    1.613    1.955    94.5    30.2  15.9
2025 02 14    02 20.13   +51 50.1    1.811    2.018    87.1    29.3  16.2
2025 02 24    02 25.09   +53 53.9    2.005    2.086    80.6    27.9  16.6
2025 03 06    02 33.89   +55 56.2    2.191    2.158    75.0    26.4  16.9
2025 03 16    02 46.04   +57 58.9    2.367    2.233    70.0    24.8  17.2
2025 03 26    03 01.35   +60 02.1    2.534    2.311    65.7    23.2  17.4
2025 04 05    03 19.86   +62 05.2    2.690    2.391    62.1    21.7  17.7
2025 04 15    03 41.75   +64 06.8    2.835    2.473    59.0    20.4  17.9
2025 04 25    04 07.40   +66 04.4    2.970    2.557    56.6    19.2  18.1
2025 05 05    04 37.31   +67 55.1    3.095    2.643    54.7    18.1  18.3
2025 05 15    05 11.98   +69 34.7    3.210    2.729    53.3    17.3  18.5
2025 05 25    05 51.77   +70 58.4    3.318    2.816    52.4    16.6  18.7
2025 06 04    06 36.55   +72 00.5    3.417    2.904    52.0    16.0  18.9
2025 06 14    07 25.28   +72 36.0    3.510    2.993    51.9    15.5  19.0


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

                         (C) Copyright 2024 CBAT
2024 July 20                     (CBET 5419)              Daniel W. E. Green