[Iaude] CBET 5383: COMET C/2024 G2

quai at eps.harvard.edu quai at eps.harvard.edu
Wed Apr 17 16:49:49 EDT 2024


                                                  Electronic Telegram No. 5383
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 G2 (ATLAS)
     An apparently asteroidal object discovered on CCD images taken on Apr. 8
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 CCD astrometrists elsewhere after it
was posted to the Minor Planet Center's PCCP webpage due to its nearly
parabolic orbit.  The discovery observations are tabulated below:

     2024 UT             R.A. (2000) Decl.       Mag.
     Apr.  8.32961   13 11 46.85   -78 23 51.9   18.6
           8.34785   13 11 42.53   -78 23 45.6   18.8
           8.36604   13 11 38.35   -78 23 39.8   18.9

S. Deen (Simi Valley, CA, USA) writes that he obtained four 600-s exposures
with a 0.43-m reflector located at Rio Hurtado, Chile, on Apr. 9.12-9.15 UT
that show obvious cometary activity with a coma of size 3".5 in 2".5 seeing,
along with a tail about 10" long in p.a. 160 degrees; the measured V magnitude
was 19.1-19.3.  Eight stacked 60-s exposures taken remotely by H. Sato
(Bunkyo-ku, Tokyo, Japan) with a "Deep Sky Chile" 0.51-m f/6.8 astrograph
located at Rio Hurtado on Apr. 9.37 show a strongly condensed coma 7" in
diameter with no tail; the magnitude was 18.8 as measured within a circular
aperture of radius 3".6.  Twenty-three 180-s exposures taken remotely by A.
Aletti, L. Buzzi, F. Bellini, and G. Galli on Apr. 12.1 with a 0.36-m f/8.4
reflector located at Hakos, Namibia, show a condensed coma 8" wide (full-
width-at-half-maximum 5".0 in 3".7 seeing); the magnitude was measured to be
18.5-18.8.  T. Prystavski (Lviv, Ukraine) writes that ten stacked 120-s
exposures taken on each of two nights (Apr. 12.5 and 13.6) with a 0.32-m f/9
Ritchey-Chretien telescope at Siding Spring, NSW, Australia, show an
apparently stellar head of total mag 19.1-19.2 with an apparent "spike" (tail)
toward p.a. 175 degrees.
     The available astrometry appears on MPEC 2024-H20.  The following
parabolic orbital elements by S. Nakano (Central Bureau) are from 50
observations spanning 2024 Apr. 8-16 (mean residual 0".3).  There are no close
approaches to major planets.

     T = 2025 June 13.93448 TT        Peri. = 328.89517
                                      Node  = 171.38175 2000.0
     q = 5.3399077 AU                 Incl. = 122.13455

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.
2024 03 31    13 45.34   -78 55.2    5.911    6.240   104.7     8.9  18.2
2024 04 10    13 05.31   -78 14.4    5.794    6.204   109.7     8.7  18.2
2024 04 20    12 30.25   -76 56.2    5.695    6.167   113.7     8.6  18.1
2024 04 30    12 03.21   -75 06.2    5.616    6.132   116.5     8.5  18.0
2024 05 10    11 44.30   -72 52.6    5.561    6.097   117.8     8.4  18.0
2024 05 20    11 32.25   -70 23.7    5.529    6.062   117.4     8.5  18.0
2024 05 30    11 25.45   -67 47.0    5.523    6.029   115.5     8.7  18.0
2024 06 09    11 22.57   -65 08.8    5.540    5.995   112.1     9.0  17.9
2024 06 19    11 22.57   -62 34.0    5.578    5.963   107.5     9.4  17.9
2024 06 29    11 24.68   -60 06.7    5.635    5.931   102.1     9.7  17.9
2024 07 09    11 28.35   -57 49.8    5.707    5.900    96.0     9.9  17.9
2024 07 19    11 33.17   -55 45.4    5.790    5.869    89.5    10.0  18.0
2024 07 29    11 38.84   -53 54.5    5.879    5.839    82.8     9.9  18.0
2024 08 08    11 45.12   -52 17.6    5.971    5.810    76.0     9.8  18.0
2024 08 18    11 51.83   -50 54.8    6.061    5.782    69.3     9.4  18.0
2024 08 28    11 58.81   -49 45.6    6.146    5.754    62.8     9.0  18.0
2024 09 07    12 05.96   -48 49.3    6.220    5.728    56.6     8.4  18.0
2024 09 17    12 13.14   -48 05.1    6.282    5.702    50.9     7.9  18.0
2024 09 27    12 20.25   -47 32.0    6.327    5.676    45.9     7.3  18.0
2024 10 07    12 27.20   -47 09.0    6.355    5.652    42.0     6.8  18.0
2024 10 17    12 33.87   -46 55.2    6.362    5.628    39.4     6.5  18.0
2024 10 27    12 40.14   -46 49.4    6.348    5.605    38.5     6.3  18.0
2024 11 06    12 45.89   -46 50.7    6.312    5.584    39.5     6.5  18.0
2024 11 16    12 50.98   -46 58.0    6.254    5.562    42.3     6.9  17.9
2024 11 26    12 55.24   -47 10.0    6.173    5.542    46.7     7.4  17.9
2024 12 06    12 58.50   -47 25.6    6.071    5.523    52.2     8.1  17.9
2024 12 16    13 00.56   -47 43.3    5.951    5.505    58.7     8.8  17.8
2024 12 26    13 01.22   -48 01.4    5.814    5.487    66.0     9.4  17.7
2025 01 05    13 00.25   -48 17.8    5.663    5.471    73.8     9.9  17.7
2025 01 15    12 57.45   -48 30.0    5.504    5.455    82.0    10.3  17.6
2025 01 25    12 52.68   -48 34.8    5.340    5.440    90.6    10.4  17.5
2025 02 04    12 45.86   -48 28.7    5.177    5.427    99.5    10.3  17.4
2025 02 14    12 37.07   -48 07.4    5.021    5.414   108.4    10.0  17.4


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

                         (C) Copyright 2024 CBAT
2024 April 17                    (CBET 5383)              Daniel W. E. Green




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