[Iaude] CBET 5399: COMET C/2024 J4

quai at eps.harvard.edu quai at eps.harvard.edu
Wed May 29 22:29:44 EDT 2024


                                                  Electronic Telegram No. 5399
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 J4 (LEMMON)
     An apparently asteroidal object discovered by K. W. Wierzchos on CCD
images obtained on May 11 with the Mt. Lemmon Survey 1.5-m reflector has been
found to show cometary appearance elsewhere after posting on the Minor
Planet Center's NEOCP and PCCP webpages.  Wierzchos flagged the object as a
possible near-earth-object candidate, through which it was posted to the
NEOCP.  The discovery observations are tabulated below.

     2024 UT             R.A. (2000) Decl.       Mag.   Observer
     May  11.41593   19 03 43.51   +44 49 07.2   20.1   Wierzchos
          11.42072   19 03 43.25   +44 49 09.9   20.1     "
          11.42553   19 03 42.96   +44 49 11.7   20.4     "

Ten stacked 120-s CCD exposures taken on May 12.4 UT by H. Sato (Tokyo, Japan)
with a 0.43-m f/6.8 astrograph located at the Utah Desert Remote Observatory
(near Beryl Junction, UT, USA) show only a stellar appearance; the magnitude
was 19.8 as measured within a circular aperture of radius 5".7.  A. F.
Tubbiolo reports that eighteen stacked broadband 60-s CCD exposures taken on
May 17.5 in 1".2 seeing with the Bok 2.3-m f/9 reflector of Spacewatch and
Steward Observatory on Kitt Peak show a coma and tail approximately 15" long
in p.a. 140 degrees.  Additional exposures taken on May 28.34-28.36 by
Tubbiolo show a a tight coma and braad tail approximately 18" long, spanning
p.a. 110-170 degrees.
     The available astrometry appears on MPEC 2024-K128.  The following
parabolic orbital elements by S. Nakano (Central Bureau) are from 93
observations spanning 2024 May 11-28 (mean residual 0".3).  Theese elements
indicate that the comet passed 3.77 AU from Uranus in 2015 April.

     T = 2025 Apr. 27.72117 TT        Peri. = 128.07744
                                      Node  =  19.31476 2000.0
     q = 5.6878424 AU                 Incl. = 117.53510

The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 9.5 and 2.5n = 8 for the magnitudes.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2024 05 10    19 05.13   +44 39.6    6.006    6.223    97.7     9.3  19.7
2024 05 20    18 54.38   +45 42.1    5.906    6.195   101.9     9.2  19.7
2024 05 30    18 41.81   +46 30.2    5.821    6.167   105.3     9.1  19.6
2024 06 09    18 27.72   +46 59.8    5.752    6.140   107.9     9.1  19.6
2024 06 19    18 12.65   +47 07.4    5.702    6.114   109.3     9.0  19.6
2024 06 29    17 57.27   +46 51.3    5.673    6.088   109.5     9.1  19.5
2024 07 09    17 42.29   +46 11.5    5.665    6.063   108.4     9.2  19.5
2024 07 19    17 28.35   +45 09.6    5.677    6.039   106.1     9.3  19.5
2024 07 29    17 15.96   +43 49.2    5.708    6.015   102.8     9.5  19.5
2024 08 08    17 05.42   +42 14.4    5.756    5.993    98.6     9.6  19.5
2024 08 18    16 56.87   +40 29.7    5.818    5.971    93.8     9.7  19.5
2024 08 28    16 50.28   +38 39.6    5.890    5.949    88.5     9.8  19.5
2024 09 07    16 45.53   +36 48.1    5.969    5.929    82.9     9.7  19.6
2024 09 17    16 42.45   +34 58.4    6.051    5.909    77.1     9.5  19.6
2024 09 27    16 40.84   +33 13.2    6.132    5.890    71.5     9.3  19.6
2024 10 07    16 40.49   +31 34.5    6.208    5.872    65.9     8.9  19.6
2024 10 17    16 41.21   +30 03.9    6.276    5.854    60.8     8.5  19.6
2024 10 27    16 42.78   +28 42.6    6.333    5.838    56.2     8.1  19.6
2024 11 06    16 45.04   +27 31.3    6.375    5.822    52.3     7.7  19.6
2024 11 16    16 47.81   +26 30.8    6.402    5.807    49.4     7.4  19.6
2024 11 26    16 50.90   +25 41.4    6.410    5.793    47.8     7.2  19.6
2024 12 06    16 54.18   +25 03.3    6.399    5.780    47.5     7.2  19.6
2024 12 16    16 57.46   +24 36.8    6.369    5.768    48.8     7.4  19.6
2024 12 26    17 00.59   +24 21.8    6.319    5.756    51.4     7.7  19.6
2025 01 05    17 03.39   +24 18.3    6.249    5.746    55.2     8.1  19.6


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

                         (C) Copyright 2024 CBAT
2024 May 30                      (CBET 5399)              Daniel W. E. Green




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