[Iaude] CBET 5398: COMET C/2024 J3

quai at eps.harvard.edu quai at eps.harvard.edu
Wed May 29 11:54:00 EDT 2024


                                                  Electronic Telegram No. 5398
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 J3 (ATLAS)
     A comet discovered on CCD images taken on May 6.3 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
reported to the Minor Planet Center (cf. MPEC 2024-K118).  James Robinson
reported that the four stacked 30-s discovery images taken in 5".7 seeing
show a head of size 9".0 (full-width-at-half-maximum).  The discovery
observations are tabulated below:

     2024 UT             R.A. (2000) Decl.       Mag.
     May   6.26497   19 28 46.96   -42 55 22.4   17.6
           6.26678   19 28 47.03   -42 55 23.3   18.6
           6.26964   19 28 46.87   -42 55 23.8   17.1
           6.27477   19 28 46.78   -42 55 23.9   18.0

After the comet was posted on the MPC's PCCP webpage, other CCD astrometrists
also commented on the cometary appearance.  Six stacked 120-s exposures taken
remotely by H. Sato (Bunkyo-ku, Tokyo, Japan) with a 0.51-m f/6.8 astrograph
at Siding Spring, NSW, Australia, on May 12.8 UT show a strongly condensed
coma 8" in diameter with no tail; the magnitude was 17.8 as measured within a
circular aperture of radius 7".6.  Seventy-five stacked 60-s exposures taken
by A. Aletti, F. Bellini, L. Buzzi, G. Galli, and M. Auteri using a 0.36-m
f/7.5 reflector at Hakos, Namibia, on May 19.0 show a condensed 6" coma with
a faint, straight tail at least 12" long in p.a. 220 degrees.
     The following parabolic orbital elements by S. Nakano (Central Bureau)
are from 70 observations spanning May 6-28 (mean residual 0".5).  There are no
close approaches to major planets.

     T = 2026 Nov. 24.92260 TT        Peri. =  74.11797
                                      Node  = 285.98343 2000.0
     q = 3.8620938 AU                 Incl. =  75.56342

The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 6.0 and 2.5n = 8 for the magnitudes.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2024 05 10    19 27.81   -42 56.8    7.771    8.324   120.1     6.0  17.8
2024 05 20    19 24.43   -42 59.8    7.583    8.262   129.4     5.4  17.7
2024 05 30    19 19.96   -43 00.7    7.413    8.200   138.6     4.7  17.7
2024 06 09    19 14.51   -42 58.3    7.266    8.139   147.3     3.9  17.6
2024 06 19    19 08.27   -42 51.2    7.146    8.077   154.8     3.1  17.5
2024 06 29    19 01.50   -42 38.3    7.054    8.015   159.7     2.5  17.5
2024 07 09    18 54.49   -42 19.0    6.992    7.953   159.7     2.5  17.4
2024 07 19    18 47.56   -41 53.1    6.960    7.891   154.7     3.2  17.4
2024 07 29    18 41.04   -41 20.9    6.958    7.829   147.1     4.0  17.4
2024 08 08    18 35.21   -40 43.1    6.982    7.767   138.2     5.0  17.3
2024 08 18    18 30.30   -40 01.0    7.031    7.706   128.8     5.9  17.3
2024 08 28    18 26.46   -39 15.8    7.100    7.644   119.2     6.6  17.3
2024 09 07    18 23.79   -38 28.7    7.185    7.582   109.6     7.2  17.3
2024 09 17    18 22.32   -37 40.9    7.280    7.520   100.0     7.6  17.3
2024 09 27    18 22.03   -36 53.1    7.382    7.458    90.5     7.7  17.3
2024 10 07    18 22.86   -36 06.1    7.485    7.396    81.1     7.7  17.3
2024 10 17    18 24.74   -35 20.2    7.584    7.334    71.8     7.4  17.3
2024 10 27    18 27.55   -34 35.6    7.676    7.273    62.6     7.0  17.3
2024 11 06    18 31.20   -33 52.3    7.755    7.211    53.6     6.4  17.3


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

                         (C) Copyright 2024 CBAT
2024 May 29                      (CBET 5398)              Daniel W. E. Green




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