Electronic Telegram No. 5485
Central Bureau for Astronomical Telegrams
Mailing address: Hoffman Lab 209; Harvard University;
20 Oxford St.; Cambridge, MA 02138; U.S.A.
e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network
COMET P/2024 X3 (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 on Dec. 8 (discovery
observations tabulated below). Three 45-s w-band survey images taken in
1".3-1".4 seeing show a condensed coma of size 2".2 (full-width-at-half-
maximum) with a straight tail 6" long in p.a. 290 degrees.
2024 UT R.A. (2000) Decl. Mag.
Dec. 8.57146 10 25 18.30 +11 09 06.4 21.0
8.58428 10 25 18.85 +11 09 04.3 20.7
8.59706 10 25 19.39 +11 09 02.1 21.5
Weryk adds that four 45-s w-band Pan-STARRS2 survey images taken in 1".2-1".4
seeing on Dec. 25.5 UT show this to be clearly a comet, with stacked images
showing a condensed coma of size 1".8 (FWHM) and a straight tail 7" long in
p.a. 300 degrees. Weryk also identified three earlier single-night sets of
observations in the Minor Planet Center's "isolated tracklet file": from
Oct. 22.5 (at mag 20.6-20.9) and Dec. 1.5 (mag 20.6-20.9) with the 2.25-m Bok
reflector at Kitt Peak, and on Nov. 14.5 (at mag 20.3) with the 1.5-m Mt.
Lemmon reflector. After the comet was posted on the MPC's PCCP webpage, H.
Sato (Bunkyo-ku, Tokyo, Japan) stacked sixteen 60-s CCD exposures taken
remotely on Dec. 10.55 UT with a 0.43-m f/6.8 astrograph located at the Utah
Desert Remote Observatory (near Beryl Junction, UT, USA) to find only a
stellar appearance; the magnitude was 20.6 as measured within a circular
aperture of radius 3".8. The available astrometry appears on MPEC 2024-Y145.
The following orbital elements by S. Nakano (Central Bureau) are from 36
observations spanning 2024 Oct. 22-Dec. 25 (mean residual 0".5). There
are no close approaches to major planets.
T = 2024 Sept. 5.77794 TT Peri. = 352.94391
e = 0.6237783 Node = 113.35696 2000.0
q = 2.6131967 AU Incl. = 2.97221
a = 6.9458949 AU n = 0.05384083 P = 18.31 years
The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 15.0 and 2.5n = 8 for the
magnitudes.
Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag.
2024 12 16 10 30.06 +10 52.3 2.264 2.746 109.0 19.8 20.3
2024 12 26 10 34.56 +10 41.0 2.171 2.773 118.1 18.2 20.2
2025 01 05 10 36.74 +10 43.8 2.089 2.801 127.8 16.1 20.2
2025 01 15 10 36.59 +11 00.4 2.022 2.832 138.1 13.4 20.1
2025 01 25 10 34.26 +11 29.3 1.975 2.864 148.9 10.2 20.1
2025 02 04 10 30.10 +12 07.4 1.951 2.898 160.2 6.6 20.1
2025 02 14 10 24.72 +12 49.9 1.953 2.933 171.5 2.9 20.2
2025 02 24 10 18.89 +13 31.6 1.983 2.970 175.4 1.5 20.3
2025 03 06 10 13.41 +14 07.8 2.041 3.009 164.6 5.0 20.4
2025 03 16 10 09.02 +14 34.7 2.126 3.049 153.6 8.3 20.5
2025 03 26 10 06.19 +14 50.2 2.235 3.090 143.0 11.2 20.7
2025 04 05 10 05.23 +14 53.7 2.364 3.132 132.9 13.5 20.8
2025 04 15 10 06.19 +14 45.5 2.511 3.176 123.4 15.3 21.0
2025 04 25 10 08.97 +14 26.6 2.672 3.220 114.4 16.5 21.2
2025 05 05 10 13.41 +13 58.0 2.843 3.265 105.8 17.3 21.4
2025 05 15 10 19.28 +13 21.0 3.020 3.311 97.7 17.6 21.6
2025 05 25 10 26.36 +12 36.6 3.202 3.358 90.0 17.6 21.7
2025 06 04 10 34.45 +11 45.8 3.385 3.406 82.6 17.2 21.9
2025 06 14 10 43.35 +10 49.6 3.567 3.454 75.4 16.5 22.1
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2024 CBAT
2024 December 28 (CBET 5485) Daniel W. E. Green