[Iaude] CBET 5333: COMET C/2024 A1

quai at eps.harvard.edu quai at eps.harvard.edu
Sun Jan 21 17:53:04 EST 2024


                                                  Electronic Telegram No. 5333
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 A1 (ATLAS)
     A new comet has been discovered on CCD images obtained 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.  A. Fitzsimmons
reported that four 30-s images taken on Jan. 3.2 UT show the object as being
"slightly soft" with a size of 6".3 (full-width-at-half-maximum) in 4".3
seeing.  The discovery observations are tabulated below:

     2024 UT             R.A. (2000) Decl.       Mag.
     Jan.  3.20752    7 05 23.35   -65 42 33.4   18.8
           3.21123    7 05 22.85   -65 42 33.3   18.7
           3.24216    7 05 20.04   -65 42 26.2   18.8
           3.24854    7 05 19.31   -65 42 25.2   18.8

After the object was posted on the Minor Planet Center's PCCP webpage, other
CCD astrometrists have commented on the object's appearance, as follows.
Eight stacked 60-s exposures taken remotely by Hidetaka Sato (Bunkyo-ku,
Tokyo, Japan) using a 0.51-m f/6.8 astrograph located at Rio Hurtado on Jan.
4.30 UT show a strongly condensed coma 8" in diameter with a hint of tail 5"
long toward p.a. 300 degrees; the magnitude was 18.5 as measured within a
circular aperture of radius 4".3.  Exposures taken remotely by A. Hale
(Cloudcroft, NM, USA) on Jan. 5.1 using a 0.35-m reflector located at
Sutherland, South Africa, show the object to be slightly non-stellar, with
a small hint of diffuseness, when compared to stars of similar brightness,
and no tail.  Twenty-one 60-s exposurse taken in 3".4 seeing by A. Aletti,
F. Bellini, L. Buzzi, and G. Galli on Jan. 10.9 remotely using a 0.36-m f/8.4
Ritchey-Chretien reflector located at Hakos, Namibia, show a slightly
condensed coma of size 4".8 (FWHM) that extends toward the north.
     The available astrometry appears on MPEC 2024-B78.  The following
parabolic orbital elements by S. Nakano (Central Bureau) are from 93
observations spanning 2024 Jan. 3-19 (mean residual 0".4).

     T = 2025 June 13.86526 TT        Peri. = 353.31775
                                      Node  = 112.15936 2000.0
     q = 3.8754626 AU                 Incl. =  94.44347

The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 8.0 and 2.5n = 8 for the magnitudes.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2023 12 02    07 50.27   -65 43.4    6.076    6.063    84.6     9.3  18.2
2023 12 07    07 44.63   -65 56.4    6.027    6.033    85.7     9.4  18.1
2023 12 12    07 38.36   -66 05.3    5.978    6.004    86.8     9.4  18.1
2023 12 17    07 31.54   -66 09.6    5.929    5.974    87.9     9.5  18.1
2023 12 22    07 24.26   -66 08.8    5.881    5.945    88.9     9.5  18.0
2023 12 27    07 16.66   -66 02.3    5.834    5.915    90.0     9.6  18.0
2024 01 01    07 08.86   -65 50.0    5.787    5.886    90.9     9.6  18.0
2024 01 06    07 01.01   -65 31.4    5.742    5.857    91.9     9.7  17.9
2024 01 11    06 53.26   -65 06.4    5.698    5.828    92.7     9.7  17.9
2024 01 16    06 45.77   -64 35.0    5.655    5.798    93.5     9.7  17.9
2024 01 21    06 38.65   -63 57.2    5.615    5.769    94.1     9.8  17.8
2024 01 26    06 32.03   -63 13.3    5.577    5.740    94.6     9.8  17.8
2024 01 31    06 25.99   -62 23.7    5.541    5.712    95.0     9.9  17.8
2024 02 05    06 20.59   -61 28.6    5.507    5.683    95.3     9.9  17.7
2024 02 10    06 15.86   -60 28.6    5.476    5.654    95.3    10.0  17.7
2024 02 15    06 11.84   -59 24.1    5.448    5.625    95.3    10.1  17.7
2024 02 20    06 08.52   -58 15.8    5.423    5.597    95.0    10.1  17.7
2024 02 25    06 05.88   -57 04.1    5.400    5.568    94.6    10.2  17.6
2024 03 01    06 03.90   -55 49.7    5.381    5.540    94.1    10.3  17.6
2024 03 06    06 02.55   -54 33.0    5.364    5.512    93.3    10.4  17.6
2024 03 11    06 01.79   -53 14.7    5.351    5.483    92.4    10.4  17.6
2024 03 16    06 01.59   -51 55.2    5.340    5.455    91.4    10.5  17.5
2024 03 21    06 01.90   -50 35.0    5.333    5.427    90.2    10.6  17.5
2024 03 26    06 02.68   -49 14.7    5.327    5.400    88.8    10.6  17.5
2024 03 31    06 03.89   -47 54.6    5.325    5.372    87.3    10.7  17.5
2024 04 05    06 05.49   -46 35.2    5.325    5.344    85.7    10.8  17.5
2024 04 10    06 07.46   -45 16.7    5.327    5.317    84.0    10.8  17.4
2024 04 15    06 09.75   -43 59.6    5.331    5.289    82.2    10.8  17.4
2024 04 20    06 12.33   -42 44.3    5.336    5.262    80.3    10.8  17.4
2024 04 25    06 15.17   -41 30.8    5.343    5.235    78.4    10.9  17.4
2024 04 30    06 18.25   -40 19.5    5.352    5.208    76.4    10.8  17.4
2024 05 05    06 21.54   -39 10.6    5.361    5.181    74.4    10.8  17.4
2024 05 10    06 25.02   -38 04.2    5.370    5.154    72.3    10.8  17.3
2024 05 15    06 28.66   -37 00.5    5.380    5.127    70.2    10.7  17.3
2024 05 20    06 32.44   -35 59.7    5.390    5.101    68.2    10.6  17.3
2024 05 25    06 36.34   -35 01.8    5.399    5.075    66.1    10.5  17.3
2024 05 30    06 40.35   -34 06.8    5.408    5.049    64.1    10.4  17.3
2024 06 04    06 44.45   -33 14.9    5.416    5.023    62.1    10.3  17.3
2024 06 09    06 48.62   -32 26.0    5.422    4.997    60.2    10.2  17.3
2024 06 14    06 52.84   -31 40.3    5.427    4.971    58.4    10.0  17.2
2024 06 19    06 57.10   -30 57.6    5.431    4.945    56.7     9.9  17.2
2024 06 24    07 01.39   -30 18.0    5.432    4.920    55.0     9.7  17.2
2024 06 29    07 05.70   -29 41.4    5.431    4.895    53.5     9.6  17.2
2024 07 04    07 10.00   -29 07.9    5.427    4.870    52.2     9.5  17.2
2024 07 09    07 14.29   -28 37.3    5.420    4.845    51.0     9.4  17.2
2024 07 14    07 18.56   -28 09.6    5.411    4.820    50.0     9.3  17.1
2024 07 19    07 22.78   -27 44.8    5.398    4.796    49.2     9.2  17.1
2024 07 24    07 26.95   -27 22.7    5.382    4.772    48.6     9.2  17.1
2024 07 29    07 31.06   -27 03.3    5.363    4.748    48.3     9.2  17.1


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

                         (C) Copyright 2024 CBAT
2024 January 21                  (CBET 5333)              Daniel W. E. Green




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