[Iaude] CBET 5329: COMET P/2023 Y2
quai at eps.harvard.edu
quai at eps.harvard.edu
Sat Jan 13 18:09:00 EST 2024
Electronic Telegram No. 5329
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 P/2023 Y2 (GIBBS)
Alexander R. Gibbs reports his discovery of a comet on CCD images
obtained on 2023 Dec. 17 with the Mt. Lemmon Survey's 1.5-m reflector in great
seeing conditions (astrometry tabulated below). The comet showed a condensed
coma of size 5' with a slightly fanned and curved tail 40" long in p.a. 295
degrees.
2023 UT R.A. (2000) Decl. Mag. Observer
Dec. 17.47372 10 59 42.19 +14 17 32.8 19.4 Gibbs
17.47888 10 59 42.45 +14 17 32.8 "
17.48404 10 59 42.67 +14 17 32.3 "
17.48920 10 59 42.86 +14 17 32.5 "
After the comet was posted on the Minor Planet Center's PCCP webpage, other
CCD astrometrists have reported cometary appearance to the Central Bureau.
R. Weryk (Department of Physics and Astronomy, University of Western Ontario)
found pre-discovery observations of the comet in images obtained on 2023 Dec.
13.6 UT in very poor conditions with the Pan-STARRS1 1.8-m Ritchey-Chretien
reflector at Haleakala; four 45-s w-band survey images taken in 1".9 seeing
show a diffuse coma of size about 2".5 (full-width-at-half-maximum) with a
broad tail > 10" long in p.a. 275-305 degrees. Four additional 45-s w-band
survey images taken with the Pan-STARRS2 1.8-m Ritchey-Chretien reflector at
Haleakala on Dec. 17.6 in 1".5 seeing show a diffuse coma of size 2".0 (FWHM)
with a straight 10" tail in p.a. 300 degrees.
Twelve stacked 60-s exposures taken remotely by Hidetaka Sato (Bunkyo-ku,
Tokyo, Japan) with a 0.51-m f/6.8 astrograph on 2023 Dec. 17.7 UT show a
poorly condensed coma 12" in diameter with a faint 3'.0 tail toward p.a. 295
degrees; the magnitude was 19.6 as measured within a circular aperture of
radius 6".5. Twenty stacked 90-s exposures taken by T. Ikemura with a 0.38-m
f/4.2 reflector at Shinshiro, Japan, on 2024 Jan. 11.7 (and measured by
Hirohisa Sato) show a condensed coma about 9" in diameter and a hint of a tail
about 13" long toward p.a. 297 degrees; the total magnitude was measured to be
19.4. One-hundred-ninety-nine stacked 30-s exposures taken by A. Aletti with
a 0.36-m f/7.5 reflector at Varese, Italy, on 2024 Jan. 4.2 (and measured with
M. Auteri) show a diffuse 7" coma with a broad, fan-shaped tail at least 25"
long centered around p.a. 300 degrees.
Additional astrometry of the comet, imaged as an apparently stellar
object, was found in the MPC's "isolated tracklet file" for 2022 Oct. 23 UT
(Pan-STARRS2 reflector; mag 21.9-22.2) and 2022 Dec. 20 (Mt. Lemmon Survey
reflector; mag 20.8-21.4). The available astrometry appears on MPEC 2024-A148.
The following elliptical orbital elements by S. Nakano (Central Bureau)
are from 56 observations spanning 2022 Oct. 23-2024 Jan. 12 (mean residual
0".6), which indicate that the comet passed 0.030 AU from Jupiter in 1973
January and 0.15 AU from Jupiter on 2020 Feb. 28. Orbital elements prior to
the 1973 encounter suggest e = 0.32, q = 2.63 AU, i = 9.6 deg, and P = 7.6 yr.
The 2022 observations show residuals of -0.19 deg in R.A. and -0.09 deg in
Decl. from an orbit computed only with the available 2023-2024 observations.
Epoch = 2015 June 27.0 TT
T = 2015 June 28.54390 TT Peri. = 2.55022
e = 0.1535860 Node = 102.60233 2000.0
q = 3.7743195 AU Incl. = 14.49583
a = 4.4591882 AU n = 0.10466956 P = 9.42 years
Epoch = 2023 Aug. 4.0 TT
T = 2023 Aug. 9.79773 TT Peri. = 16.78813
e = 0.3920926 Node = 79.23106 2000.0
q = 2.2758828 AU Incl. = 6.99276
a = 3.7437986 AU n = 0.13606153 P = 7.24 years
Epoch = 2030 Oct. 26.0 TT
T = 2030 Nov. 13.66151 TT Peri. = 16.91369
e = 0.3907447 Node = 79.19469 2000.0
q = 2.2862654 AU Incl. = 6.98616
a = 3.7525572 AU n = 0.13558545 P = 7.27 years
Epoch = 2038 Feb. 26.0 TT
T = 2038 Feb. 12.28766 TT Peri. = 16.81147
e = 0.3922982 Node = 79.20341 2000.0
q = 2.2766310 AU Incl. = 6.99038
a = 3.7462965 AU n = 0.13592547 P = 7.25 years
The following ephemeris by the undersigned from the above orbital elements
uses photometric power-law parameters H = 14.0 and 2.5n = 10 for the
magnitudes.
Date TT R. A. (2000) Decl. Delta r Elong. Phase Mag.
2023 12 02 10 45.25 +14 42.0 2.169 2.414 92.0 24.1 19.5
2023 12 12 10 55.18 +14 22.3 2.070 2.438 99.7 23.5 19.4
2023 12 22 11 02.92 +14 17.2 1.974 2.463 108.0 22.3 19.4
2024 01 01 11 08.24 +14 28.1 1.884 2.489 116.9 20.6 19.3
2024 01 11 11 10.91 +14 55.3 1.805 2.517 126.5 18.3 19.3
2024 01 21 11 10.78 +15 37.9 1.739 2.546 136.7 15.4 19.3
2024 01 31 11 07.93 +16 32.0 1.692 2.576 147.3 11.9 19.3
2024 02 10 11 02.71 +17 32.3 1.667 2.608 157.8 8.2 19.3
2024 02 20 10 55.78 +18 31.1 1.667 2.640 166.9 4.9 19.3
2024 03 01 10 48.11 +19 20.9 1.695 2.673 168.3 4.3 19.4
2024 03 11 10 40.73 +19 55.9 1.750 2.706 160.5 7.0 19.5
2024 03 21 10 34.59 +20 12.9 1.830 2.741 150.4 10.3 19.7
2024 03 31 10 30.36 +20 11.3 1.933 2.776 140.3 13.3 19.9
2024 04 10 10 28.36 +19 52.8 2.056 2.812 130.5 15.7 20.1
2024 04 20 10 28.66 +19 19.6 2.194 2.848 121.2 17.6 20.3
2024 04 30 10 31.11 +18 34.4 2.345 2.884 112.5 18.8 20.5
2024 05 10 10 35.46 +17 39.3 2.504 2.921 104.2 19.6 20.6
2024 05 20 10 41.45 +16 36.3 2.669 2.958 96.4 19.9 20.8
2024 05 30 10 48.80 +15 26.8 2.837 2.995 89.0 19.8 21.0
2024 06 09 10 57.25 +14 12.2 3.006 3.033 81.8 19.3 21.2
2024 06 19 11 06.61 +12 53.3 3.174 3.071 74.9 18.6 21.4
2024 06 29 11 16.68 +11 31.2 3.338 3.109 68.3 17.7 21.5
2024 07 09 11 27.32 +10 06.4 3.498 3.146 61.7 16.5 21.7
2024 07 19 11 38.43 +08 39.8 3.651 3.184 55.3 15.2 21.8
2024 07 29 11 49.88 +07 12.0 3.796 3.222 49.0 13.8 22.0
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2021 CBAT
2021 January 13 (CBET 5329) Daniel W. E. Green
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