[Iaude] CBET 5391: COMET C/2024 G5

quai at eps.harvard.edu quai at eps.harvard.edu
Thu May 9 21:55:10 EDT 2024


                                                  Electronic Telegram No. 5391
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 G5 (LEONARD)
     G. J. Leonard reports his discovery of a comet on CCD images obtained on
Apr. 5 with the Mt. Lemmon Survey's 1.5-m reflector in Arizona (discovery
observations tabulted below); four 30-s co-added images showed a moderately
condensed coma 8" across with a straight tail 6" long in p.a. 90 degrees.

     2024 UT             R.A. (2000) Decl.       Mag.   Observer
     Apr.  5.13126    7 44 13.51   +29 28 22.6   20.8   Leonard
           5.13876    7 44 13.61   +29 28 17.4   20.9     "
           5.14407    7 44 13.65   +29 28 12.1   20.3     "
           5.14940    7 44 13.67   +29 28 07.5            "
           5.15838    7 44 13.84   +29 28 00.3   19.9     "
           5.16979    7 44 13.90   +29 27 51.0   19.9     "
           5.18147    7 44 14.05   +29 27 41.5   19.9     "
           5.19316    7 44 14.18   +29 27 31.7   20.3     "

After the comet was posted on the Minor Planet Center's PCCP webpage, other
CCD astrometrists also commented on the cometary appearance.  Eight stacked
120-s exposurse taken remotely by H. Sato (Bunkyo-ku, Tokyo, Japan) on Apr.
10.2 UT with a 0.43-m f/6.8 astrograph located at the Utah Desert Remote
Observatory (near Beryl Junction, UT, USA) showed only a stellar appearance;
the magnitude was 20.3 as measured within a circular aperture of radius 3".8.
K. Wierzchos writes that four 30-s unfiltered exposures taken with the Mt.
Lemmon 1.5-m reflector on Apr. 21.2 show a condensed 6" coma with no tail.
     Numerous single-night, previously unconnected observations (all with the
comet presumably stellar in appearance) were subsequently identified in the
MPC's "isolated tracklet file", including astrometry obtained with the
Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala on 2023 Dec. 15.6
UT (mag 21.7-22.1), 2024 Jan. 3.5 (mag 21.2-21.3), and Feb. 5.4 (mag 20.6-
20.9); with the Pan-STARRS1 1.8-m Ritchey-Chretien reflector at Haleakala
on 2024 Jan. 6.5 (mag21.2-21.5); and with the Mt. Lemmon 1.5-m reflector on
Feb. 17.2 (mag 20.1-20.8).  S. Deen (Simi Valley, CA, USA) also identified
a several pre-discovery observations (all of which showed the comet as
stellar in appearance) in publicly available images obtained with the 1.2-m
Oschin Schmidt reflector at Palomar (ZTF program) from 2024 Jan. 6.4 (mag
r = 21.2), Jan. 13.4 (r = 20.4), Jan. 15.3 (r = 20.2), Jan. 17.4 (g = 20.9),
and Jan. 31.4.  The available astrometry appears on MPEC 2024-J126.
     The following orbital elements by S. Nakano (Central Bureau) are from 92
observations spanning 2023 Dec. 15-2024 May 5 (mean residual 0".4), with
corresponding "original" and "future" values of 1/a being +0.002396 and
+0.001629 (+/- 0.000008) AU**-1, respectively.  There are no close approaches
to any major planets.

                    Epoch = 2024 Sept. 7.0 TT
     T = 2024 Sept. 7.00060 TT        Peri. = 209.56253
     e = 0.9945486                    Node  = 316.39844 2000.0
     q = 2.9528710 AU                 Incl. =  50.38911

The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 13.0 and 2.5n = 8 for the
magnitudes.

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase  Mag.
2024 05 10    08 01.93   +21 45.3    3.410    3.184    68.6    17.2  19.7
2024 05 15    08 05.91   +20 40.8    3.459    3.166    64.9    16.8  19.7
2024 05 20    08 10.16   +19 36.5    3.507    3.148    61.3    16.4  19.7
2024 05 25    08 14.65   +18 32.2    3.552    3.132    57.8    15.9  19.7
2024 05 30    08 19.35   +17 27.8    3.596    3.116    54.3    15.3  19.7
2024 06 04    08 24.24   +16 23.2    3.638    3.100    50.9    14.7  19.7
2024 06 09    08 29.32   +15 18.1    3.677    3.086    47.7    14.1  19.7
2024 06 14    08 34.55   +14 12.5    3.713    3.072    44.4    13.4  19.7
2024 06 19    08 39.92   +13 06.3    3.747    3.058    41.3    12.7  19.8

2024 11 06    11 28.04   -26 42.7    3.603    3.013    46.8    13.9  19.6
2024 11 11    11 33.69   -28 30.4    3.570    3.023    49.5    14.4  19.6
2024 11 16    11 39.22   -30 19.3    3.537    3.034    52.3    14.9  19.6
2024 11 21    11 44.64   -32 09.3    3.503    3.046    55.0    15.4  19.6
2024 11 26    11 49.91   -34 00.4    3.470    3.058    57.7    15.8  19.6
2024 12 01    11 55.02   -35 52.2    3.436    3.072    60.4    16.2  19.6
2024 12 06    11 59.94   -37 44.8    3.403    3.085    63.1    16.6  19.6
2024 12 11    12 04.64   -39 37.8    3.370    3.100    65.9    16.8  19.6
2024 12 16    12 09.09   -41 31.0    3.337    3.116    68.6    17.1  19.6
2024 12 21    12 13.27   -43 24.2    3.306    3.132    71.3    17.3  19.6
2024 12 26    12 17.12   -45 17.2    3.275    3.148    73.9    17.5  19.6
2024 12 31    12 20.61   -47 09.6    3.246    3.166    76.6    17.6  19.6
2025 01 05    12 23.68   -49 01.1    3.217    3.184    79.2    17.7  19.6
2025 01 10    12 26.27   -50 51.2    3.190    3.202    81.8    17.7  19.6
2025 01 15    12 28.33   -52 39.6    3.165    3.221    84.4    17.7  19.6
2025 01 20    12 29.78   -54 25.7    3.142    3.241    86.9    17.6  19.6
2025 01 25    12 30.55   -56 09.2    3.120    3.262    89.4    17.6  19.6
2025 01 30    12 30.55   -57 49.3    3.100    3.283    91.8    17.5  19.6
2025 02 04    12 29.70   -59 25.5    3.083    3.304    94.2    17.3  19.6
2025 02 09    12 27.93   -60 57.0    3.067    3.326    96.5    17.1  19.6
2025 02 14    12 25.15   -62 23.1    3.054    3.349    98.7    17.0  19.6
2025 02 19    12 21.33   -63 43.2    3.044    3.372   100.8    16.7  19.6
2025 02 24    12 16.40   -64 56.4    3.036    3.395   102.8    16.5  19.7
2025 03 01    12 10.40   -66 01.9    3.031    3.419   104.7    16.3  19.7
2025 03 06    12 03.37   -66 59.0    3.028    3.444   106.5    16.0  19.7
2025 03 11    11 55.46   -67 47.1    3.028    3.468   108.2    15.8  19.7
2025 03 16    11 46.85   -68 25.8    3.031    3.494   109.7    15.5  19.8
2025 03 21    11 37.80   -68 54.9    3.036    3.520   111.1    15.3  19.8
2025 03 26    11 28.61   -69 14.5    3.045    3.546   112.3    15.1  19.8
2025 03 31    11 19.61   -69 24.7    3.056    3.572   113.4    14.9  19.8
2025 04 05    11 11.11   -69 26.2    3.071    3.599   114.2    14.7  19.9
2025 04 10    11 03.41   -69 19.8    3.088    3.626   115.0    14.5  19.9
2025 04 15    10 56.71   -69 06.6    3.108    3.654   115.5    14.4  20.0
2025 04 20    10 51.16   -68 47.6    3.132    3.682   115.8    14.2  20.0
2025 04 25    10 46.84   -68 23.9    3.158    3.710   115.9    14.1  20.1
2025 04 30    10 43.80   -67 56.4    3.187    3.739   115.9    14.0  20.1
2025 05 05    10 42.00   -67 26.2    3.220    3.768   115.7    14.0  20.1
2025 05 10    10 41.40   -66 54.3    3.255    3.797   115.3    13.9  20.2
2025 05 15    10 41.91   -66 21.4    3.293    3.826   114.7    13.9  20.3
2025 05 20    10 43.45   -65 48.1    3.334    3.856   113.9    13.9  20.3
2025 05 25    10 45.94   -65 15.0    3.377    3.886   113.0    13.9  20.4


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

                         (C) Copyright 2024 CBAT
2024 May 10                      (CBET 5391)              Daniel W. E. Green




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