[Iaude] CBET 5390: COMET C/2024 G4
quai at eps.harvard.edu
quai at eps.harvard.edu
Thu May 9 16:43:22 EDT 2024
Electronic Telegram No. 5390
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 G4 (PANSTARRS)
R. Weryk, Department of Physics and Astronomy, University of Western
Ontario, reports the discovery of another comet in images obtained with the
Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala (discovery
observations tabulated below). The four 45-s w-band survey images taken in
1".4 seeing showed a diffuse coma of size 2".4 (full-width-at-half-maximum)
with a 4" tail toward p.a. 225 degrees.
2024 UT R.A. (2000) Decl. Mag.
Apr. 10.54008 14 48 26.30 +18 41 58.5 21.1
10.55254 14 48 26.08 +18 42 01.9 21.0
10.56509 14 48 25.92 +18 42 04.8 21.1
10.57765 14 48 25.67 +18 42 08.0 20.9
Weryk subsequently identified Pan-STARRS2 observations of this comet on
numerous dates from 2022 Feb. 9 (mag 21.7-22.7) to 2024 Mar. 31 (mag 20.9),
as well as observations obtained with the Pan-STARRS1 1.8-m Ritchey-Chretien
reflector at Haleakala on 2023 Mar. 13 (mag 21.3) and 2024 Apr. 6 (mag 20.0-
21.2). He notes that the comet appears "fuzzy" in most of those images,
though it is faint and difficult to get an accurate measurement of coma size.
Weryk adds that follow-up images of the comet were obtained on 2024 May 4.26
UT with the 3.6-m Canada-France-Hawaii Telescope at Mauna Kea, in which three
60-s gri-band images taken by queue observer A. Achohido (queue coordinator
T. Burdullis; PI R. Wainscoat) in 0".8 seeing show a very condensed head of
size 1".5 (FWHM) and a broad 4"-long tail spanning p.a. 200-280 degrees.
After the comet was posted on the Minor Planet Center's PCCP webpage,
other CCD astrometrists commented on the cometary appearance. Ten stacked
120-s exposures taken remotely on 2024 Apr. 17.5 UT by H. Sato (Bunkyo-ku,
Tokyo, Japan) 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 20.3 as measured within
a circular aperture of radius 4".9. Two-hundred-ninety-seven 30-s stacked
exposures taken on 2024 Apr. 19.1 by A. Aletti with a 0.36-m f/7.5 reflector
at Varese, Italy, show this to be clearly a comet despite moonlight, with a
diffuse 7" coma and a faint, fan-shaped tail at least 10" long in p.a. about
220 degrees; the magnitude was measured to be 19.8-20.0 (measurements by
Aletti and M. Auteri).
Observations of this comet were subsequently identified in the MPC's
"isolated tracklet file" that were taken on 2024 Mar. 19.4 UT by the Mt.
Lemmon Survey (magnitude 20.5-21.1). S. Deen (Simi Valley, CA, USA) also
identified a stellar pre-discovery image of this comet obtained with the CFHT
on 2021 Jan. 12.6 (magnitude r = 23.8).
The available astrometry appears on MPEC 2024-J123. The following
orbital elements by S. Nakano (Central Bureau) are from 93 observations
spanning 2021 Jan. 12-2024 May 6 (mean residual 0".4), with corresponding
"original" and "future" values of 1/a being +0.000030 and +0.000028 (+/-
0.000004) AU**-1, respectively. There are no close approaches to any major
planets.
Epoch = 2026 Mar. 21.0 TT
T = 2026 Mar. 21.47299 TT Peri. = 131.41062
e = 0.9985975 Node = 152.97180 2000.0
q = 4.9006523 AU Incl. = 33.02841
The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 9.0 and 2.5n = 8 for the magnitudes.
Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag.
2024 03 31 14 51.00 +17 56.2 6.471 7.270 140.6 5.0 19.9
2024 04 10 14 48.59 +18 39.8 6.377 7.219 144.8 4.6 19.9
2024 04 20 14 45.64 +19 17.6 6.308 7.167 146.5 4.4 19.8
2024 04 30 14 42.37 +19 47.8 6.265 7.117 145.3 4.6 19.8
2024 05 10 14 38.99 +20 09.0 6.247 7.066 141.6 5.1 19.8
2024 05 20 14 35.72 +20 20.4 6.252 7.015 136.0 5.7 19.7
2024 05 30 14 32.79 +20 21.6 6.278 6.965 129.3 6.5 19.7
2024 06 09 14 30.39 +20 12.8 6.323 6.915 122.0 7.1 19.7
2024 06 19 14 28.68 +19 54.7 6.383 6.865 114.4 7.7 19.7
2024 06 29 14 27.78 +19 28.2 6.454 6.816 106.7 8.2 19.7
2024 07 09 14 27.74 +18 54.5 6.534 6.766 98.9 8.5 19.7
2024 07 19 14 28.63 +18 14.9 6.618 6.718 91.3 8.7 19.7
2024 07 29 14 30.42 +17 30.7 6.703 6.669 83.7 8.7 19.7
2024 08 08 14 33.11 +16 43.1 6.787 6.621 76.3 8.6 19.7
2024 08 18 14 36.65 +15 53.3 6.865 6.573 69.1 8.3 19.7
2024 08 28 14 40.99 +15 02.5 6.936 6.525 62.1 7.9 19.7
2024 09 07 14 46.08 +14 11.5 6.997 6.478 55.4 7.4 19.7
2024 09 17 14 51.85 +13 21.3 7.046 6.431 48.9 6.8 19.7
2024 09 27 14 58.23 +12 32.8 7.081 6.384 42.9 6.1 19.7
2025 01 05 16 19.33 +08 32.0 6.515 5.942 50.8 7.4 19.3
2025 01 15 16 27.31 +08 43.5 6.373 5.901 57.3 8.1 19.2
2025 01 25 16 34.86 +09 02.4 6.222 5.860 64.2 8.7 19.1
2025 02 04 16 41.89 +09 28.6 6.062 5.819 71.2 9.2 19.0
2025 02 14 16 48.26 +10 01.8 5.898 5.780 78.3 9.6 18.9
2025 02 24 16 53.87 +10 41.2 5.731 5.740 85.6 9.9 18.9
2025 03 06 16 58.61 +11 26.2 5.565 5.702 92.9 10.0 18.8
2025 03 16 17 02.38 +12 15.3 5.402 5.664 100.3 10.0 18.7
2025 03 26 17 05.10 +13 07.2 5.246 5.627 107.5 9.7 18.6
2025 04 05 17 06.70 +13 59.9 5.099 5.590 114.6 9.4 18.5
2025 04 15 17 07.17 +14 51.3 4.965 5.555 121.4 8.9 18.4
2025 04 25 17 06.53 +15 39.0 4.847 5.520 127.7 8.3 18.4
2025 05 05 17 04.86 +16 20.3 4.747 5.485 133.1 7.7 18.3
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2024 CBAT
2024 May 9 (CBET 5390) Daniel W. E. Green
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