[Iaude] CBET 5394: COMET C/2024 J2

[quai at eps.harvard.edu]

                                                  Electronic Telegram No. 5394
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 J2 (WIERZCHOS)
     Kacper W. Wierzchos, Lunar and Planetary Laboratory, University of
Arizona, reports his discovery of another comet on CCD images obtained on May
11 with the Mt. Lemmon Survey's 1.5-m reflector (discovery observations
tabulated below); there was a 5" coma, and a suspected 7" tail spanning p.a.
220-250 degrees in four 30-s unfiltered exposures, but there was a very bright
sky background due to strong aurora borealis.

     2024 UT             R.A. (2000) Decl.       Mag.   Observer
     May  11.26844   14 15 42.94   +47 26 27.6   21.2   Wierzchos
          11.27403   14 15 42.59   +47 26 29.5   19.9     "
          11.27958   14 15 42.11   +47 26 32.1   19.9     "
          11.28502   14 15 41.88   +47 26 34.1   20.1     "

Follow-up CCD observations obtained by Wierzchos on May 14.2 UT with the 1.0-m
reflector of Steward Observatory at Mt. Lemmon show a diffuse 7" coma and no
tail (magnitude 19.9-20.2).
     After the comet was posted to the Minor Planet Center's PCCP webpage,
H. Sato (Bunkyo-ku, Tokyo, Japan) reported that twelve stacked 120-s CCD
exposures taken remotely on May 12.3 UT with a 0.43-m f/6.8 astrograph
located at the Utah Desert Remote Observatory (near Beryl Junction, UT, USA)
show a strongly condensed coma 8" in diameter with no tail; the magnitude was
20.5 as measured within a circular aperture of radius 5".7.
     Presumably asteroidal pre-discovery images of this comet were
subsequently reported to the MPC, which were made with the Pan-STARRS2 1.8-m
Ritchey-Chretien reflector at Haleakala on Mar. 18.6 UT (mag 21.0-22.0), Mar.
29.6 (mag 21.4), Apr. 20.6 (mag 22.0), and Apr. 26.5 (mag 21.2), and also with
the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala on Apr. 27.6
(mag 21.1).  The available astrometry appears on MPEC 2024-K31.
     The following unperturbed orbital elements by S. Nakano (Central Bureau)
are from 57 observations spanning 2024 Mar. 18-May 19 (mean residual 0".5).
There are no close approaches to major planets.

     T = 2025 Mar. 19.72247 TT        Peri. = 143.16322
     e = 0.9877339                    Node  = 189.05375 2000.0
     q = 1.8104420 AU                 Incl. =  79.28734

The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 12.0 and 2.5n = 8 for the
magnitudes.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2024 05 10    14 17.06   +47 17.2    3.501    4.021   114.1    13.3  19.6
2024 05 20    14 06.63   +48 17.8    3.498    3.932   108.1    14.2  19.5
2024 05 30    13 57.02   +48 51.2    3.505    3.842   101.8    15.0  19.4
2024 06 09    13 48.93   +48 59.8    3.519    3.753    95.4    15.6  19.3
2024 06 19    13 42.87   +48 47.4    3.535    3.663    89.1    16.1  19.3
2024 06 29    13 39.14   +48 18.6    3.549    3.574    83.2    16.4  19.2
2024 07 09    13 37.86   +47 37.2    3.558    3.484    77.6    16.6  19.1
2024 07 19    13 39.05   +46 47.1    3.560    3.395    72.5    16.6  19.0
2024 07 29    13 42.59   +45 51.4    3.551    3.305    67.9    16.5  18.9
2024 08 08    13 48.39   +44 52.3    3.531    3.216    63.9    16.4  18.8
2024 08 18    13 56.36   +43 52.0    3.498    3.128    60.6    16.4  18.7
2024 08 28    14 06.39   +42 52.0    3.452    3.039    58.0    16.4  18.6
2024 09 07    14 18.45   +41 53.4    3.393    2.952    56.1    16.5  18.4
2024 09 17    14 32.54   +40 57.3    3.321    2.865    54.9    16.7  18.3
2024 09 27    14 48.66   +40 04.0    3.239    2.779    54.5    17.1  18.1
2024 10 07    15 06.90   +39 14.1    3.147    2.694    54.6    17.6  17.9
2024 10 17    15 27.34   +38 27.6    3.048    2.610    55.2    18.3  17.8
2024 10 27    15 50.10   +37 44.1    2.945    2.528    56.1    19.0  17.6
2024 11 06    16 15.28   +37 02.6    2.841    2.449    57.1    19.9  17.4
2024 11 16    16 42.93   +36 22.0    2.741    2.371    58.0    20.7  17.2
2024 11 26    17 13.01   +35 40.0    2.649    2.296    58.7    21.5  17.0
2024 12 06    17 45.36   +34 54.4    2.568    2.224    58.8    22.3  16.8
2024 12 16    18 19.59   +34 02.8    2.504    2.157    58.3    22.9  16.7
2024 12 26    18 55.16   +33 03.1    2.458    2.093    57.1    23.2  16.5
2025 01 05    19 31.34   +31 54.7    2.432    2.034    55.0    23.3  16.4


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

                         (C) Copyright 2024 CBAT
2024 May 20                      (CBET 5394)              Daniel W. E. Green